diff --git a/src/filesystem/filesystem.c b/src/filesystem/filesystem.c
index cd523b81..ecfe8e5b 100644
--- a/src/filesystem/filesystem.c
+++ b/src/filesystem/filesystem.c
@@ -1,14 +1,20 @@
 #include "filesystem.h"
 #include "../util.h"
 #include <physfs.h>
+#include <stdio.h>
 #ifdef __APPLE__
 #include <mach-o/dyld.h>
 #endif
 
+static FilesystemState state;
+
 void lovrFilesystemInit(const char* arg0) {
   if (!PHYSFS_init(arg0)) {
     error("Could not initialize filesystem: %s", PHYSFS_getLastError());
   }
+
+  state.gameSource = NULL;
+  state.identity = NULL;
 }
 
 void lovrFilesystemDestroy() {
@@ -19,16 +25,38 @@ int lovrFilesystemExists(const char* path) {
   return PHYSFS_exists(path);
 }
 
-const char* lovrFilesystemGetExecutablePath() {
+int lovrFilesystemGetExecutablePath(char* dest, unsigned int size) {
 #ifdef __APPLE__
-  char* path = malloc(1024);
-  uint32_t size = sizeof(path);
-  if (_NSGetExecutablePath(path, &size) == 0) {
-    return path;
+  if (_NSGetExecutablePath(dest, &size) == 0) {
+    return 0;
   }
 #endif
 
-  return NULL;
+  return 1;
+}
+
+const char* lovrFilesystemGetIdentity() {
+  return state.identity;
+}
+
+const char* lovrFilesystemGetRealDirectory(const char* path) {
+  if (!PHYSFS_isInit()) {
+    return NULL;
+  }
+
+  return PHYSFS_getRealDir(path);
+}
+
+const char* lovrFilesystemGetSource() {
+  return state.gameSource;
+}
+
+const char* lovrFilesystemGetUserDirectory() {
+  if (!PHYSFS_isInit()) {
+    return NULL;
+  }
+
+  return PHYSFS_getUserDir();
 }
 
 int lovrFilesystemIsDirectory(const char* path) {
@@ -40,6 +68,9 @@ int lovrFilesystemIsFile(const char* path) {
 }
 
 void* lovrFilesystemRead(const char* path, int* bytesRead) {
+  if (!PHYSFS_isInit()) {
+    return NULL;
+  }
 
   // Open file
   PHYSFS_file* handle = PHYSFS_openRead(path);
@@ -72,6 +103,44 @@ void* lovrFilesystemRead(const char* path, int* bytesRead) {
   return data;
 }
 
-int lovrFilesystemSetSource(const char* source) {
-  return PHYSFS_mount(source, NULL, 0);
+int lovrFilesystemSetIdentity(const char* identity) {
+  state.identity = identity;
+
+  // Unmount old write directory
+  if (state.savePathFull && state.savePathRelative) {
+    PHYSFS_removeFromSearchPath(state.savePathRelative);
+  } else {
+    state.savePathRelative = malloc(LOVR_PATH_MAX);
+    state.savePathFull = malloc(LOVR_PATH_MAX);
+  }
+
+  // Set new write directory
+#ifdef __APPLE__
+  const char* userDir = PHYSFS_getUserDir();
+  PHYSFS_setWriteDir(userDir);
+
+  snprintf(state.savePathRelative, LOVR_PATH_MAX, "Library/Application Support/LOVR/%s", identity);
+  PHYSFS_mkdir(state.savePathRelative);
+
+  snprintf(state.savePathFull, LOVR_PATH_MAX, "%s%s", userDir, state.savePathRelative);
+  if (PHYSFS_setWriteDir(state.savePathFull)) {
+    PHYSFS_mount(state.savePathFull, NULL, 0);
+    return 0;
+  }
+#endif
+
+  return 1;
+}
+
+int lovrFilesystemSetSource(const char* source) {
+  if (state.gameSource) {
+    return 1;
+  }
+
+  if (PHYSFS_mount(source, NULL, 0)) {
+    state.gameSource = source;
+    return 0;
+  }
+
+  return 1;
 }
diff --git a/src/filesystem/filesystem.h b/src/filesystem/filesystem.h
index ef9c494d..69071d65 100644
--- a/src/filesystem/filesystem.h
+++ b/src/filesystem/filesystem.h
@@ -1,8 +1,27 @@
+#ifndef LOVR_FILESYSTEM_TYPES
+#define LOVR_FILESYSTEM_TYPES
+
+#define LOVR_PATH_MAX 1024
+
+typedef struct {
+  const char* gameSource;
+  const char* identity;
+  char* savePathRelative;
+  char* savePathFull;
+} FilesystemState;
+
+#endif
+
 void lovrFilesystemInit(const char* arg0);
 void lovrFilesystemDestroy();
 int lovrFilesystemExists(const char* path);
-const char* lovrFilesystemGetExecutablePath();
+int lovrFilesystemGetExecutablePath(char* dest, unsigned int size);
+const char* lovrFilesystemGetIdentity();
+const char* lovrFilesystemGetRealDirectory(const char* path);
+const char* lovrFilesystemGetSource();
+const char* lovrFilesystemGetUserDirectory();
 int lovrFilesystemIsDirectory(const char* path);
 int lovrFilesystemIsFile(const char* path);
 void* lovrFilesystemRead(const char* path, int* bytesRead);
+int lovrFilesystemSetIdentity(const char* identity);
 int lovrFilesystemSetSource(const char* source);
diff --git a/src/lovr.c b/src/lovr.c
index e5e94f4e..4d19306e 100644
--- a/src/lovr.c
+++ b/src/lovr.c
@@ -67,6 +67,8 @@ void lovrInit(lua_State* L, int argc, char** argv) {
     "  end "
     "end "
 
+    "lovr.filesystem.setIdentity(conf.identity or 'default') "
+
     "function lovr.run() "
     "  if lovr.load then lovr.load() end "
     "  while true do "
diff --git a/src/lovr/filesystem.c b/src/lovr/filesystem.c
index 8b26eb2c..7c5b3089 100644
--- a/src/lovr/filesystem.c
+++ b/src/lovr/filesystem.c
@@ -51,9 +51,14 @@ const luaL_Reg lovrFilesystem[] = {
   { "init", l_lovrFilesystemInitialize },
   { "exists", l_lovrFilesystemExists },
   { "getExecutablePath", l_lovrFilesystemGetExecutablePath },
+  { "getIdentity", l_lovrFilesystemGetIdentity },
+  { "getRealDirectory", l_lovrFilesystemGetRealDirectory },
+  { "getSource", l_lovrFilesystemGetSource },
+  { "getUserDirectory", l_lovrFilesystemGetUserDirectory },
   { "isDirectory", l_lovrFilesystemIsDirectory },
   { "isFile", l_lovrFilesystemIsFile },
   { "read", l_lovrFilesystemRead },
+  { "setIdentity", l_lovrFilesystemSetIdentity },
   { "setSource", l_lovrFilesystemSetSource },
   { NULL, NULL }
 };
@@ -88,10 +93,22 @@ int l_lovrFilesystemExists(lua_State* L) {
 }
 
 int l_lovrFilesystemGetExecutablePath(lua_State* L) {
-  const char* exePath = lovrFilesystemGetExecutablePath();
+  char buffer[1024];
 
-  if (exePath) {
-    lua_pushstring(L, exePath);
+  if (lovrFilesystemGetExecutablePath(buffer, sizeof(buffer))) {
+    lua_pushnil(L);
+  } else {
+    lua_pushstring(L, buffer);
+  }
+
+  return 1;
+}
+
+int l_lovrFilesystemGetIdentity(lua_State* L) {
+  const char* identity = lovrFilesystemGetIdentity();
+
+  if (identity) {
+    lua_pushstring(L, identity);
   } else {
     lua_pushnil(L);
   }
@@ -99,6 +116,36 @@ int l_lovrFilesystemGetExecutablePath(lua_State* L) {
   return 1;
 }
 
+int l_lovrFilesystemGetRealDirectory(lua_State* L) {
+  const char* path = luaL_checkstring(L, 1);
+  const char* realDirectory = lovrFilesystemGetRealDirectory(path);
+
+  if (realDirectory) {
+    lua_pushstring(L, realDirectory);
+  } else {
+    lua_pushnil(L);
+  }
+
+  return 1;
+}
+
+int l_lovrFilesystemGetSource(lua_State* L) {
+  const char* source = lovrFilesystemGetSource();
+
+  if (source) {
+    lua_pushstring(L, source);
+  } else {
+    lua_pushnil(L);
+  }
+
+  return 1;
+}
+
+int l_lovrFilesystemGetUserDirectory(lua_State* L) {
+  lua_pushstring(L, lovrFilesystemGetUserDirectory());
+  return 1;
+}
+
 int l_lovrFilesystemIsDirectory(lua_State* L) {
   const char* path = luaL_checkstring(L, 1);
   lua_pushboolean(L, lovrFilesystemIsDirectory(path));
@@ -114,23 +161,27 @@ int l_lovrFilesystemIsFile(lua_State* L) {
 int l_lovrFilesystemRead(lua_State* L) {
   const char* path = luaL_checkstring(L, 1);
   int size;
-  char* contents = lovrFilesystemRead(path, &size);
-  if (!contents) {
+  char* content = lovrFilesystemRead(path, &size);
+  if (!content) {
     return luaL_error(L, "Could not read file '%s'", path);
   }
 
-  lua_pushlstring(L, contents, size);
+  lua_pushlstring(L, content, size);
   return 1;
 }
 
+int l_lovrFilesystemSetIdentity(lua_State* L) {
+  const char* identity = luaL_checkstring(L, 1);
+
+  if (lovrFilesystemSetIdentity(identity)) {
+    return luaL_error(L, "Could not set the filesystem identity");
+  }
+
+  return 0;
+}
+
 int l_lovrFilesystemSetSource(lua_State* L) {
-  const char* source = lua_tostring(L, 1);
-
-  if (source) {
-    lua_pushboolean(L, lovrFilesystemSetSource(source));
-  } else {
-    lua_pushboolean(L, 0);
-  }
-
+  const char* source = luaL_checkstring(L, 1);
+  lua_pushboolean(L, !lovrFilesystemSetSource(source));
   return 1;
 }
diff --git a/src/lovr/filesystem.h b/src/lovr/filesystem.h
index a9a565cd..e8ae0843 100644
--- a/src/lovr/filesystem.h
+++ b/src/lovr/filesystem.h
@@ -7,7 +7,12 @@ int l_lovrFilesystemInit(lua_State* L);
 int l_lovrFilesystemInitialize(lua_State* L);
 int l_lovrFilesystemExists(lua_State* L);
 int l_lovrFilesystemGetExecutablePath(lua_State* L);
+int l_lovrFilesystemGetIdentity(lua_State* L);
+int l_lovrFilesystemGetRealDirectory(lua_State* L);
+int l_lovrFilesystemGetSource(lua_State* L);
+int l_lovrFilesystemGetUserDirectory(lua_State* L);
 int l_lovrFilesystemIsDirectory(lua_State* L);
 int l_lovrFilesystemIsFile(lua_State* L);
 int l_lovrFilesystemRead(lua_State* L);
+int l_lovrFilesystemSetIdentity(lua_State* L);
 int l_lovrFilesystemSetSource(lua_State* L);