diff --git a/src/app/app.h b/src/app/app.h
index fa5371ce..e951dec7 100644
--- a/src/app/app.h
+++ b/src/app/app.h
@@ -5,8 +5,6 @@
 #include "../platform/platform.h"
 #include "../ttf/ttf.h"
 #include "../gpu/gpu.h"
-#include "../sim/sim.h"
-#include "../user/user.h"
 #include "../sprite/sprite.h"
 #include "../watch/watch.h"
 #include "../draw/draw.h"
@@ -18,6 +16,7 @@
 #include "../net/net.h"
 #include "../resource/resource.h"
 #include "../playback/playback.h"
+#include "../pp/pp.h"
 
 #include "app_core.h"
 
diff --git a/src/app/app_core.c b/src/app/app_core.c
index a8a2bdc3..7e6fc259 100644
--- a/src/app/app_core.c
+++ b/src/app/app_core.c
@@ -150,11 +150,11 @@ void P_AppStartup(String args_str)
         }
     }
 
-    (UNUSED)args;
-    (UNUSED)logfile_name;
-    (UNUSED)settings_file_name;
-    (UNUSED)connect_address;
-    (UNUSED)GetDefaultAppWindowSettings;
+    (MaybeUnused)args;
+    (MaybeUnused)logfile_name;
+    (MaybeUnused)settings_file_name;
+    (MaybeUnused)connect_address;
+    (MaybeUnused)GetDefaultAppWindowSettings;
 
 #if !RtcIsEnabled
     /* Verify test modes aren't left on by accident in release mode */
@@ -240,17 +240,17 @@ void P_AppStartup(String args_str)
     TTF_StartupReceipt ttf_sr           = TTF_Startup();
     F_StartupReceipt font_sr            = F_Startup(&asset_cache_sr, &ttf_sr);
     S_StartupReceipt sprite_sr          = S_Startup();
-    MIX_StartupReceipt mixer_sr           = MIX_Startup();
+    MIX_StartupReceipt mixer_sr         = MIX_Startup();
     SND_StartupReceipt sound_sr         = SND_Startup(&asset_cache_sr);
     D_StartupReceipt draw_sr            = D_Startup(&font_sr);
-    SimStartupReceipt sim_sr            = sim_startup();
-
+    
     /* Interface systems */
+    SimStartupReceipt sim_sr            = SimStartup();
     PB_StartupReceipt playback_sr       = PB_Startup(&mixer_sr);
-    UserStartupReceipt user_sr = StartupUser(&font_sr, &sprite_sr, &draw_sr, &asset_cache_sr, &sound_sr, &mixer_sr, &sim_sr, connect_address);
+    UserStartupReceipt user_sr          = StartupUser(&font_sr, &sprite_sr, &draw_sr, &asset_cache_sr, &sound_sr, &mixer_sr, &sim_sr, connect_address);
 
-    (UNUSED)user_sr;
-    (UNUSED)playback_sr;
+    (MaybeUnused)user_sr;
+    (MaybeUnused)playback_sr;
 
 #if 0
     /* Write window settings to file */
diff --git a/src/ase/ase_core.c b/src/ase/ase_core.c
index 24f4bbea..2584257d 100644
--- a/src/ase/ase_core.c
+++ b/src/ase/ase_core.c
@@ -238,8 +238,8 @@ void ASE_Inflate(u8 *dst, u8 *encoded)
 
     u8 cmf = (u8)(cm | (cinfo << 4));
     u8 flg = fcheck | (fdict << 5) | (flevl << 6);
-    (UNUSED)cmf;
-    (UNUSED)flg;
+    (MaybeUnused)cmf;
+    (MaybeUnused)flg;
     Assert(((cmf * 256) + flg) % 31 == 0);
 
     u8 bfinal = 0;
@@ -255,7 +255,7 @@ void ASE_Inflate(u8 *dst, u8 *encoded)
                 i16 len = ASE_ConsumeBits(&bb, 16);
                 i16 nlen = ASE_ConsumeBits(&bb, 16);
                 Assert(len == ~nlen);  /* Validation */
-                (UNUSED)nlen;
+                (MaybeUnused)nlen;
                 while (len-- > 0)
                 {
                     *dst++ = ASE_ConsumeBits(&bb, 8);
diff --git a/src/asset_cache/asset_cache_core.c b/src/asset_cache/asset_cache_core.c
index d120d9a0..66118744 100644
--- a/src/asset_cache/asset_cache_core.c
+++ b/src/asset_cache/asset_cache_core.c
@@ -50,7 +50,7 @@ AC_Asset *AC_GetAssetCacheSlotLocked(P_Lock *lock, String key, u64 hash)
 {
     AC_SharedState *g = &AC_shared_state;
     P_AssertLockedES(lock, &g->lookup_mutex);
-    (UNUSED)lock;
+    (MaybeUnused)lock;
 
     u64 index = hash % countof(g->lookup);
     for (;;)
diff --git a/src/base/base_arena.c b/src/base/base_arena.c
index de380047..451d934f 100644
--- a/src/base/base_arena.c
+++ b/src/base/base_arena.c
@@ -134,7 +134,7 @@ void ShrinkArena(Arena *arena)
 {
     /* Not implemented */
     Assert(0);
-    (UNUSED)arena;
+    (MaybeUnused)arena;
 }
 
 void SetArenaReadonly(Arena *arena)
diff --git a/src/base/base_arena.h b/src/base/base_arena.h
index b0a450f6..431877e7 100644
--- a/src/base/base_arena.h
+++ b/src/base/base_arena.h
@@ -205,7 +205,7 @@ Inline TempArena _BeginScratch(Arena *potential_conflict)
     _BeginScratchNoConflict(); \
     do { \
         u8 arena = 0; \
-        (UNUSED)arena; \
+        (MaybeUnused)arena; \
     } while (0)
 
 Inline TempArena _BeginScratchNoConflict(void)
diff --git a/src/base/base_buddy.c b/src/base/base_buddy.c
index dc950a5d..ca9fc2bb 100644
--- a/src/base/base_buddy.c
+++ b/src/base/base_buddy.c
@@ -161,7 +161,7 @@ BuddyBlock *GetUnusedBuddyBlock(BuddyCtx *ctx, BuddyLevel *level)
             left->parent = parent_block;
             left->memory = parent_block->memory;
 
-            /* Create right (UNUSED) block from parent block */
+            /* Create right (MaybeUnused) block from parent block */
             BuddyBlock *right = PushBuddyBlock(ctx);
             right->is_used = 0;
             right->level = level;
@@ -196,7 +196,7 @@ BuddyBlock *GetUnusedBuddyBlock(BuddyCtx *ctx, BuddyLevel *level)
             left->level = level;
             left->memory = ArenaBase(arena);
 
-            /* Create right (UNUSED) block from new arena memory */
+            /* Create right (MaybeUnused) block from new arena memory */
             BuddyBlock *right = PushBuddyBlock(ctx);
             right->is_used = 0;
             right->level = level;
diff --git a/src/base/base_core.h b/src/base/base_core.h
index bfa7c8f3..cd305ac6 100644
--- a/src/base/base_core.h
+++ b/src/base/base_core.h
@@ -133,7 +133,7 @@ extern "C" {
 #  define Assert(cond) ((cond) ? 1 : (__builtin_trap(), 0))
 #  define DEBUGBREAK __builtin_debugtrap()
 # endif
-# define DEBUGBREAKABLE { volatile i32 __DEBUGBREAKABLE_VAR = 0; (UNUSED) __DEBUGBREAKABLE_VAR; } (void)0
+# define DEBUGBREAKABLE { volatile i32 __DEBUGBREAKABLE_VAR = 0; (MaybeUnused) __DEBUGBREAKABLE_VAR; } (void)0
 #else
 # define Assert(cond) (void)(0)
 #endif
@@ -238,7 +238,13 @@ void __asan_unpoison_memory_region(void const volatile *add, size_t);
 #endif
 
 //- Markup
-#define UNUSED void
+#define MaybeUnused void
+
+#if CompilerIsClang
+# define UNUSED __attribute((unused))
+#else
+# define UNUSED
+#endif
 
 #if CompilerIsMsvc
 # if LanguageIsCpp
diff --git a/src/base/base_string.c b/src/base/base_string.c
index d20a73bf..5f97cd10 100644
--- a/src/base/base_string.c
+++ b/src/base/base_string.c
@@ -649,7 +649,7 @@ b32 AdvanceCodepointIter(CodepointIter *iter)
 void EndCodepointIter(CodepointIter *iter)
 {
     /* Do nothing */
-    (UNUSED)iter;
+    (MaybeUnused)iter;
 }
 
 //- String decode
diff --git a/src/draw/draw_core.c b/src/draw/draw_core.c
index d5dfc5ba..4a09bc1b 100644
--- a/src/draw/draw_core.c
+++ b/src/draw/draw_core.c
@@ -7,7 +7,7 @@ D_StartupReceipt D_Startup(F_StartupReceipt *font_sr)
 {
     __prof;
     D_SharedState *g = &D_shared_state;
-    (UNUSED)font_sr;
+    (MaybeUnused)font_sr;
     u32 pixel_white = 0xFFFFFFFF;
     g->solid_white_texture = GPU_AllocTexture(GP_TEXTURE_FORMAT_R8G8B8A8_UNORM, 0, VEC2I32(1, 1), &pixel_white);
     return (D_StartupReceipt) { 0 };
@@ -116,7 +116,7 @@ void D_DrawLineGradient(GPU_RenderSig *sig, Vec2 start, Vec2 end, f32 thickness,
     D_DrawMaterial(sig, D_MATERIALPARAMS(.texture = g->solid_white_texture, .tint0 = start_color, .tint1 = end_color, .quad = quad));
 #else
     /* Placeholder */
-    (UNUSED)end_color;
+    (MaybeUnused)end_color;
     Quad quad = QuadFromLine(start, end, thickness);
     D_DrawQuad(sig, quad, start_color);
 #endif
diff --git a/src/dxc/dxc_core_win32.cpp b/src/dxc/dxc_core_win32.cpp
index a7336146..1c6d61d5 100644
--- a/src/dxc/dxc_core_win32.cpp
+++ b/src/dxc/dxc_core_win32.cpp
@@ -2,10 +2,10 @@
 
 DXC_Result DXC_Compile(Arena *arena, String shader_source, i32 num_args, String *args)
 {
-    (UNUSED)arena;
-    (UNUSED)shader_source;
-    (UNUSED)num_args;
-    (UNUSED)args;
+    (MaybeUnused)arena;
+    (MaybeUnused)shader_source;
+    (MaybeUnused)num_args;
+    (MaybeUnused)args;
     DXC_Result result = ZI;
     return result;
 }
diff --git a/src/font/font_core.c b/src/font/font_core.c
index 62f281e0..da798302 100644
--- a/src/font/font_core.c
+++ b/src/font/font_core.c
@@ -7,8 +7,8 @@ F_StartupReceipt F_Startup(AC_StartupReceipt *asset_cache_sr, TTF_StartupReceipt
 {
     __prof;
     F_SharedState *g = &F_shared_state;
-    (UNUSED)asset_cache_sr;
-    (UNUSED)ttf_sr;
+    (MaybeUnused)asset_cache_sr;
+    (MaybeUnused)ttf_sr;
     g->params.arena = AllocArena(Gibi(64));
     return (F_StartupReceipt) { 0 };
 }
diff --git a/src/gpu/gpu_dx12.c b/src/gpu/gpu_dx12.c
index fde8f86a..17e837d5 100644
--- a/src/gpu/gpu_dx12.c
+++ b/src/gpu/gpu_dx12.c
@@ -88,7 +88,7 @@ P_ExitFuncDef(GPU_D12_Shutdown)
     }
     ID3D12Device_Release(g->device);
 #else
-    (UNUSED)GPU_D12_ReleaseCommandQueue;
+    (MaybeUnused)GPU_D12_ReleaseCommandQueue;
 #endif
 
     {
@@ -339,7 +339,7 @@ void GPU_D12_InitObjects(void)
                 GPU_D12_CommandQueue *cq = g->command_queues[i];
                 String dbg_name = params[i].dbg_name;
                 __prof_dx12_ctx_alloc(cq->prof, g->device, cq->cq, dbg_name.text, dbg_name.len);
-                (UNUSED)dbg_name;
+                (MaybeUnused)dbg_name;
             }
         }
 #endif
@@ -1321,7 +1321,7 @@ GPU_D12_CpuDescriptorHeap *GPU_D12_AllocCpuDescriptorHeap(enum D3D12_DESCRIPTOR_
 void cpu_descriptor_heap_release(GPU_D12_CpuDescriptorHeap *dh)
 {
     /* TODO */
-    (UNUSED)dh;
+    (MaybeUnused)dh;
 }
 #endif
 
@@ -1556,7 +1556,7 @@ void GPU_D12_ReleaseCommandQueue(GPU_D12_CommandQueue *cq)
 {
     __prof;
     /* TODO */
-    (UNUSED)cq;
+    (MaybeUnused)cq;
     //ID3D12CommandQueue_Release(cq->cq);
 }
 
@@ -3090,7 +3090,7 @@ GPU_Swapchain *GPU_AllocSwapchain(P_Window *window, Vec2I32 resolution)
 void GPU_ReleaseSwapchain(GPU_Swapchain *gp_swapchain)
 {
     /* TODO */
-    (UNUSED)gp_swapchain;
+    (MaybeUnused)gp_swapchain;
 }
 
 void GPU_WaitOnSwapchain(GPU_Swapchain *gp_swapchain)
@@ -3102,7 +3102,7 @@ void GPU_WaitOnSwapchain(GPU_Swapchain *gp_swapchain)
         WaitForSingleObjectEx(swapchain->waitable, 1000, 1);
     }
 #else
-    (UNUSED)gp_swapchain;
+    (MaybeUnused)gp_swapchain;
 #endif
 }
 
diff --git a/src/mixer/mixer_core.c b/src/mixer/mixer_core.c
index 96827c6f..fa8606bc 100644
--- a/src/mixer/mixer_core.c
+++ b/src/mixer/mixer_core.c
@@ -57,7 +57,7 @@ MIX_Track *MIX_AllocTrackLocked(P_Lock *lock, SND_Sound *sound)
 {
     MIX_SharedState *g = &M_shared_state;
     P_AssertLockedE(lock, &g->mutex);
-    (UNUSED)lock;
+    (MaybeUnused)lock;
 
     MIX_Track *track = 0;
     if (g->track_first_free)
@@ -104,7 +104,7 @@ void MIX_ReleaseTrackLocked(P_Lock *lock, MIX_Track *track)
 {
     MIX_SharedState *g = &M_shared_state;
     P_AssertLockedE(lock, &g->mutex);
-    (UNUSED)lock;
+    (MaybeUnused)lock;
 
     /* Remove from playing list */
     MIX_Track *prev = track->prev;
diff --git a/src/platform/platform_snc.h b/src/platform/platform_snc.h
index b8419ce2..1a5b50b6 100644
--- a/src/platform/platform_snc.h
+++ b/src/platform/platform_snc.h
@@ -65,8 +65,8 @@ void P_Unlock(P_Lock *lock);
 # define P_AssertLockedE(l, m) Assert((l)->mutex == (m) && (l)->exclusive == 1)
 # define P_AssertLockedES(l, m) Assert((l)->mutex == (m))
 #else
-# define P_AssertLockedE(l, m) (UNUSED)l
-# define P_AssertLockedES(l, m) (UNUSED)l
+# define P_AssertLockedE(l, m) (MaybeUnused)l
+# define P_AssertLockedES(l, m) (MaybeUnused)l
 #endif
 
 ////////////////////////////////
diff --git a/src/platform/platform_win32.c b/src/platform/platform_win32.c
index fe2a3e4c..5ac37268 100644
--- a/src/platform/platform_win32.c
+++ b/src/platform/platform_win32.c
@@ -187,7 +187,7 @@ void P_W32_WaitReleaseThread(P_W32_Thread *thread)
     __prof;
     b32 success = P_W32_TryReleaseThread(thread, F32Infinity);
     Assert(success);
-    (UNUSED)success;
+    (MaybeUnused)success;
 }
 
 ////////////////////////////////
@@ -671,7 +671,7 @@ ForceNoInline void P_W32_FiberResume(P_W32_Fiber *fiber)
 
 void P_W32_YieldFiber(P_W32_Fiber *fiber, P_W32_Fiber *parent_fiber)
 {
-    (UNUSED)fiber;
+    (MaybeUnused)fiber;
     Assert(fiber->id == FiberId());
     Assert(parent_fiber->id == fiber->parent_id);
     Assert(parent_fiber->id > 0);
@@ -727,7 +727,7 @@ P_W32_ThreadDef(P_W32_JobWorkerEntryFunc, worker_ctx_arg)
     P_W32_WorkerCtx *ctx = worker_ctx_arg;
     P_Pool pool_kind = ctx->pool_kind;
     P_W32_JobPool *pool = &g->job_pools[pool_kind];
-    (UNUSED)ctx;
+    (MaybeUnused)ctx;
 
     {
         /* TODO: Heuristic pinning */
@@ -739,7 +739,7 @@ P_W32_ThreadDef(P_W32_JobWorkerEntryFunc, worker_ctx_arg)
             __profn("Set priority");
             b32 success = SetThreadPriority(thread_handle, pool->thread_priority) != 0;
             Assert(success);
-            (UNUSED)success;
+            (MaybeUnused)success;
         }
 
 #if 0
@@ -761,7 +761,7 @@ P_W32_ThreadDef(P_W32_JobWorkerEntryFunc, worker_ctx_arg)
             }
 #endif
             Assert(success);
-            (UNUSED)success;
+            (MaybeUnused)success;
         }
 #endif
 
@@ -772,7 +772,7 @@ P_W32_ThreadDef(P_W32_JobWorkerEntryFunc, worker_ctx_arg)
             DWORD task = 0;
             HANDLE mmc_handle = AvSetMmThreadCharacteristics(L"Pro Audio", &task);
             Assert(mmc_handle);
-            (UNUSED)mmc_handle;
+            (MaybeUnused)mmc_handle;
         }
     }
 
@@ -1107,7 +1107,7 @@ P_W32_ThreadDef(P_W32_JobSchedulerEntryFunc, _)
     {
         i32 priority = THREAD_PRIORITY_TIME_CRITICAL;
         b32 success = SetThreadPriority(GetCurrentThread(), priority);
-        (UNUSED)success;
+        (MaybeUnused)success;
         Assert(success);
     }
 
@@ -2281,7 +2281,7 @@ String P_ReadFile(Arena *arena, P_File file)
         /* TODO: error checking */
         AlignArena(arena, 16);
         s.text = PushStructsNoZero(arena, u8, size);
-        (UNUSED)ReadFile(
+        (MaybeUnused)ReadFile(
             (HANDLE)file.handle,
             s.text,
             (DWORD)s.len,
@@ -2308,7 +2308,7 @@ void P_WriteFile(P_File file, String data)
     }
 
     /* WriteFile returns TRUE on success */
-    (UNUSED)WriteFile(
+    (MaybeUnused)WriteFile(
         (HANDLE)file.handle,
         data.text,
         (DWORD)data.len,
@@ -2513,7 +2513,7 @@ P_WatchInfoList P_ReadWatchWait(Arena *arena, P_Watch *dw)
                                              0,
                                              &ov,
                                              0);
-        (UNUSED)success;
+        (MaybeUnused)success;
         Assert(success);
 
         HANDLE handles[] = {
@@ -3070,7 +3070,7 @@ void P_WriteSock(P_Sock *sock, P_Address address, String data)
     if (size != (i32)data.len)
     {
         i32 err = WSAGetLastError();
-        (UNUSED)err;
+        (MaybeUnused)err;
         Assert(0);
     }
 #endif
@@ -3373,10 +3373,10 @@ P_JobDef(P_W32_AppShutdownJob, _)
 
 int CALLBACK wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev_instance, _In_ LPWSTR cmdline_wstr, _In_ int show_code)
 {
-    (UNUSED)instance;
-    (UNUSED)prev_instance;
-    (UNUSED)cmdline_wstr;
-    (UNUSED)show_code;
+    (MaybeUnused)instance;
+    (MaybeUnused)prev_instance;
+    (MaybeUnused)cmdline_wstr;
+    (MaybeUnused)show_code;
 
     __profthread("Main thread", PROF_THREAD_GROUP_MAIN);
     P_W32_SharedCtx *g = &P_W32_shared_ctx;
@@ -3441,7 +3441,7 @@ int CALLBACK wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev_instance,
                                             }
                                         }
                                         Assert(success);
-                                        (UNUSED)success;
+                                        (MaybeUnused)success;
                                     }
                                 }
                                 CloseHandle(thread);
@@ -3543,7 +3543,7 @@ int CALLBACK wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev_instance,
 
         b32 success = RegisterRawInputDevices(&rid, 1, sizeof(rid));
         Assert(success);
-        (UNUSED)success;
+        (MaybeUnused)success;
     }
 
     /* Init threads pool */
diff --git a/src/playback/playback_win32.c b/src/playback/playback_win32.c
index a13eda2d..1676a77a 100644
--- a/src/playback/playback_win32.c
+++ b/src/playback/playback_win32.c
@@ -13,7 +13,7 @@ PB_StartupReceipt PB_Startup(MIX_StartupReceipt *mixer_sr)
 {
     __prof;
     PB_WSP_SharedState *g = &PB_WSP_shared_state;
-    (UNUSED)mixer_sr;
+    (MaybeUnused)mixer_sr;
     PB_WSP_InitializeWasapi();
     /* Start playback job */
     P_Run(1, PB_WSP_PlaybackJob, 0, P_Pool_Audio, P_Priority_High, &g->PB_WSP_PlaybackJob_counter);
diff --git a/src/pp/pp.c b/src/pp/pp.c
new file mode 100644
index 00000000..2bbe132e
--- /dev/null
+++ b/src/pp/pp.c
@@ -0,0 +1,8 @@
+#include "pp.h"
+
+#include "pp_ent.c"
+#include "pp_phys.c"
+#include "pp_step.c"
+#include "pp_space.c"
+#include "pp_sim.c"
+#include "pp_core.c"
diff --git a/src/pp/pp.h b/src/pp/pp.h
new file mode 100644
index 00000000..2cda782b
--- /dev/null
+++ b/src/pp/pp.h
@@ -0,0 +1,21 @@
+#ifndef PP_H
+#define PP_H
+
+#include "../base/base.h"
+#include "../gpu/gpu.h"
+#include "../sprite/sprite.h"
+#include "../font/font.h"
+#include "../collider/collider.h"
+#include "../draw/draw.h"
+#include "../net/net.h"
+#include "../mixer/mixer.h"
+#include "../bitbuff/bitbuff.h"
+
+#include "pp_sim.h"
+#include "pp_phys.h"
+#include "pp_space.h"
+#include "pp_ent.h"
+#include "pp_step.h"
+#include "pp_core.h"
+
+#endif
diff --git a/src/user/user_core.c b/src/pp/pp_core.c
similarity index 99%
rename from src/user/user_core.c
rename to src/pp/pp_core.c
index a0708f9f..5c699c76 100644
--- a/src/user/user_core.c
+++ b/src/pp/pp_core.c
@@ -13,13 +13,13 @@ UserStartupReceipt StartupUser(F_StartupReceipt *font_sr,
                                String connect_address_str)
 {
     __prof;
-    (UNUSED)font_sr;
-    (UNUSED)sprite_sr;
-    (UNUSED)draw_sr;
-    (UNUSED)asset_cache_sr;
-    (UNUSED)sound_sr;
-    (UNUSED)mixer_sr;
-    (UNUSED)sim_sr;
+    (MaybeUnused)font_sr;
+    (MaybeUnused)sprite_sr;
+    (MaybeUnused)draw_sr;
+    (MaybeUnused)asset_cache_sr;
+    (MaybeUnused)sound_sr;
+    (MaybeUnused)mixer_sr;
+    (MaybeUnused)sim_sr;
     SharedUserState *g = &shared_user_state;
 
     SetGstat(GSTAT_DEBUG_STEPS, U64Max);
@@ -1358,8 +1358,8 @@ void UpdateUser(P_Window *window)
                     ContactConstraint *data = &ent->contact_constraint_data;
                     Entity *e0 = sim_ent_from_id(g->ss_blended, data->e0);
                     Entity *e1 = sim_ent_from_id(g->ss_blended, data->e1);
-                    (UNUSED)e0;
-                    (UNUSED)e1;
+                    (MaybeUnused)e0;
+                    (MaybeUnused)e1;
 
 #if DeveloperIsEnabled
                     /* Draw contact points */
@@ -1433,8 +1433,8 @@ void UpdateUser(P_Window *window)
                     Entity *e1 = sim_ent_from_id(g->ss_blended, data->e1);
                     CLD_Shape e0_collider = e0->local_collider;
                     CLD_Shape e1_collider = e1->local_collider;
-                    (UNUSED)e0_collider;
-                    (UNUSED)e1_collider;
+                    (MaybeUnused)e0_collider;
+                    (MaybeUnused)e1_collider;
 
                     /* Draw closest points */
 #if 0
@@ -1538,7 +1538,7 @@ void UpdateUser(P_Window *window)
                             u32 color = collision_reuslt.solved ? Rgba32F(0, 0, 0.25, 1) : Rgba32F(0, 0.25, 0.25, 1);
                             f32 thickness = 2;
                             u32 detail = 512;
-                            (UNUSED)thickness;
+                            (MaybeUnused)thickness;
 
                             Vec2Array m = CLD_Menkowski(temp.arena, &e0_collider, &e1_collider, e0_xf, e1_xf, detail);
 
@@ -2134,7 +2134,7 @@ void GenerateuserInputCmds(Client *user_input_client, u64 tick)
 ////////////////////////////////
 //~ Sim update
 
-P_JobDef(SimJob, _)
+P_JobDef(SimJob, UNUSED job)
 {
     SharedUserState *g = &shared_user_state;
 #if 0
diff --git a/src/user/user_core.h b/src/pp/pp_core.h
similarity index 100%
rename from src/user/user_core.h
rename to src/pp/pp_core.h
diff --git a/src/sim/sim_ent.c b/src/pp/pp_ent.c
similarity index 100%
rename from src/sim/sim_ent.c
rename to src/pp/pp_ent.c
diff --git a/src/sim/sim_ent.h b/src/pp/pp_ent.h
similarity index 100%
rename from src/sim/sim_ent.h
rename to src/pp/pp_ent.h
diff --git a/src/sim/sim_phys.c b/src/pp/pp_phys.c
similarity index 99%
rename from src/sim/sim_phys.c
rename to src/pp/pp_phys.c
index 49b94d70..77fc107f 100644
--- a/src/sim/sim_phys.c
+++ b/src/pp/pp_phys.c
@@ -1013,7 +1013,7 @@ void phys_warm_start_weld_joints(PhysStepCtx *ctx)
             sim_ent_set_angular_velocity(e1, e1->angular_velocity + joint->angular_impulse1 * inv_i);
         }
 #else
-        (UNUSED)joint;
+        (MaybeUnused)joint;
 #endif
     }
 }
@@ -1260,7 +1260,7 @@ void phys_step(PhysStepCtx *ctx, f32 timestep)
             f32 earliest_toi = MaxF32(phys_determine_earliest_toi(ctx, step_dt, tolerance, max_iterations), min_toi);
             step_dt = remaining_dt * earliest_toi;
 #else
-            (UNUSED)phys_determine_earliest_toi;
+            (MaybeUnused)phys_determine_earliest_toi;
 #endif
         }
         remaining_dt -= step_dt;
diff --git a/src/sim/sim_phys.h b/src/pp/pp_phys.h
similarity index 100%
rename from src/sim/sim_phys.h
rename to src/pp/pp_phys.h
diff --git a/src/sim/sim_core.c b/src/pp/pp_sim.c
similarity index 99%
rename from src/sim/sim_core.c
rename to src/pp/pp_sim.c
index 99937e52..61f3b7e4 100644
--- a/src/sim/sim_core.c
+++ b/src/pp/pp_sim.c
@@ -52,7 +52,7 @@ Readonly Snapshot **_g_sim_snapshot_nil = &G.nil_snapshot;
 /* Accessed via `sim_ent_nil()` */
 Readonly Entity **_g_sim_ent_nil = &G.nil_ent;
 
-SimStartupReceipt sim_startup(void)
+SimStartupReceipt SimStartup(void)
 {
     __prof;
     G.nil_arena = AllocArena(Gibi(1));
diff --git a/src/sim/sim_core.h b/src/pp/pp_sim.h
similarity index 99%
rename from src/sim/sim_core.h
rename to src/pp/pp_sim.h
index 522aa938..47e7eb33 100644
--- a/src/sim/sim_core.h
+++ b/src/pp/pp_sim.h
@@ -25,7 +25,7 @@ Struct(ClientHandle) {
  * ========================== */
 
 Struct(SimStartupReceipt) { i32 _; };
-SimStartupReceipt sim_startup(void);
+SimStartupReceipt SimStartup(void);
 
 /* ========================== *
  * Client store
diff --git a/src/sim/sim_space.c b/src/pp/pp_space.c
similarity index 100%
rename from src/sim/sim_space.c
rename to src/pp/pp_space.c
diff --git a/src/sim/sim_space.h b/src/pp/pp_space.h
similarity index 100%
rename from src/sim/sim_space.h
rename to src/pp/pp_space.h
diff --git a/src/sim/sim_step.c b/src/pp/pp_step.c
similarity index 99%
rename from src/sim/sim_step.c
rename to src/pp/pp_step.c
index 4385823d..51ba1cab 100644
--- a/src/sim/sim_step.c
+++ b/src/pp/pp_step.c
@@ -170,9 +170,9 @@ internal Entity *test_spawn_employee(Entity *parent)
 
     /* Player weapon */
     if (employee->valid) {
-        (UNUSED)test_spawn_smg;
-        (UNUSED)test_spawn_launcher;
-        (UNUSED)test_spawn_chucker;
+        (MaybeUnused)test_spawn_smg;
+        (MaybeUnused)test_spawn_launcher;
+        (MaybeUnused)test_spawn_chucker;
 
         Entity *e = test_spawn_chucker(employee);
         employee->equipped = e->id;
@@ -229,7 +229,7 @@ internal void test_teleport(Entity *ent, Vec2 pos)
 
 internal void test_spawn_entities1(Entity *parent, Vec2 pos)
 {
-    (UNUSED)pos;
+    (MaybeUnused)pos;
 
     /* Enemy */
     {
@@ -242,7 +242,7 @@ internal void test_spawn_entities1(Entity *parent, Vec2 pos)
 
 internal void test_spawn_entities2(Entity *parent, Vec2 pos)
 {
-    (UNUSED)pos;
+    (MaybeUnused)pos;
 
     /* Small Box */
 #if 1
@@ -313,7 +313,7 @@ internal void test_spawn_entities2(Entity *parent, Vec2 pos)
 
 internal void test_spawn_entities3(Entity *parent, Vec2 pos)
 {
-    (UNUSED)pos;
+    (MaybeUnused)pos;
 
     /* Heavy box */
     {
@@ -338,7 +338,7 @@ internal void test_spawn_entities3(Entity *parent, Vec2 pos)
 
 internal void test_spawn_entities4(Entity *parent, Vec2 pos)
 {
-    (UNUSED)pos;
+    (MaybeUnused)pos;
 
     /* Light box */
     Entity *e = sim_ent_alloc_sync_src(parent);
diff --git a/src/sim/sim_step.h b/src/pp/pp_step.h
similarity index 100%
rename from src/sim/sim_step.h
rename to src/pp/pp_step.h
diff --git a/src/resource/resource_core.h b/src/resource/resource_core.h
index 644c080b..49d26f94 100644
--- a/src/resource/resource_core.h
+++ b/src/resource/resource_core.h
@@ -42,7 +42,7 @@ RES_StartupReceipt RES_Startup(void);
 RES_Resource RES_OpenResource(String name);
 
 #if RESOURCES_EMBEDDED
-# define RES_CloseResource(res_ptr) (UNUSED)res_ptr
+# define RES_CloseResource(res_ptr) (MaybeUnused)res_ptr
 #else
 void RES_CloseResource(RES_Resource *res_ptr);
 #endif
diff --git a/src/sim/sim.c b/src/sim/sim.c
deleted file mode 100644
index bd0084cf..00000000
--- a/src/sim/sim.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "sim.h"
-
-#include "sim_core.c"
-#include "sim_ent.c"
-#include "sim_phys.c"
-#include "sim_step.c"
-#include "sim_space.c"
diff --git a/src/sim/sim.h b/src/sim/sim.h
deleted file mode 100644
index c47255e7..00000000
--- a/src/sim/sim.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef SIM_H
-#define SIM_H
-
-#include "../base/base.h"
-#include "../sprite/sprite.h"
-#include "../collider/collider.h"
-#include "../net/net.h"
-#include "../mixer/mixer.h"
-#include "../bitbuff/bitbuff.h"
-
-#include "sim_core.h"
-#include "sim_phys.h"
-#include "sim_space.h"
-#include "sim_ent.h"
-#include "sim_step.h"
-
-#endif
diff --git a/src/sound/sound_core.c b/src/sound/sound_core.c
index e3d14d22..7c5785ad 100644
--- a/src/sound/sound_core.c
+++ b/src/sound/sound_core.c
@@ -7,7 +7,7 @@ SND_StartupReceipt SND_Startup(AC_StartupReceipt *asset_cache_sr)
 {
     __prof;
     SND_SharedState *g = &SND_shared_state;
-    (UNUSED)asset_cache_sr;
+    (MaybeUnused)asset_cache_sr;
     g->params.arena = AllocArena(Gibi(64));
     return (SND_StartupReceipt) { 0 };
 }
diff --git a/src/ttf/ttf_dwrite.cpp b/src/ttf/ttf_dwrite.cpp
index 6569f21a..045368d9 100644
--- a/src/ttf/ttf_dwrite.cpp
+++ b/src/ttf/ttf_dwrite.cpp
@@ -66,7 +66,7 @@ TTF_Result TTF_Decode(Arena *arena, String encoded, f32 point_size, u32 *cache_c
 
     /* TODO: handle errors */
     HRESULT error = 0;
-    (UNUSED)error;
+    (MaybeUnused)error;
 
     /* File */
     IDWriteFontFile *font_file = 0;
diff --git a/src/user/user.c b/src/user/user.c
deleted file mode 100644
index 204c2f4a..00000000
--- a/src/user/user.c
+++ /dev/null
@@ -1,3 +0,0 @@
-#include "user.h"
-
-#include "user_core.c"
diff --git a/src/user/user.h b/src/user/user.h
deleted file mode 100644
index e9d32d90..00000000
--- a/src/user/user.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#ifndef USER_H
-#define USER_H
-
-#include "../base/base.h"
-#include "../sim/sim.h"
-#include "../gpu/gpu.h"
-#include "../sprite/sprite.h"
-#include "../font/font.h"
-#include "../collider/collider.h"
-#include "../draw/draw.h"
-#include "../net/net.h"
-
-#include "user_core.h"
-
-#endif