diff --git a/cgdoom/cgdoom.c b/cgdoom/cgdoom.c
index 0974b0f..33922bd 100644
--- a/cgdoom/cgdoom.c
+++ b/cgdoom/cgdoom.c
@@ -384,6 +384,7 @@ int CGD_TrustUnalignedLumps = 1;
 int CGD_EnableDemos = 0;
 int CGD_SingleEpisodeUltimate = 0;
 int CGD_2MBLineMemory = 0;
+int CGD_Frameskip = 1;
 
 /* Performance counters */
 struct CGD_Perf CGD_Perf;
diff --git a/cgdoom/cgdoom.h b/cgdoom/cgdoom.h
index 8bf7e2c..4f3f345 100644
--- a/cgdoom/cgdoom.h
+++ b/cgdoom/cgdoom.h
@@ -30,6 +30,8 @@ extern int CGD_EnableDemos;
 /* The selected WAD is a split Ultimate Doom WAD with a single episode (this
    exists on the fx-CG 50 and is incorrectly detected by normal logic) */
 extern int CGD_SingleEpisodeUltimate;
+/* Skip this amount of frames after every rendered frame (default 1) */
+extern int CGD_Frameskip;
 
 // Global variables interfacing with Doom itself.
 
@@ -56,6 +58,17 @@ void UpdateKeyboardState(void);
 int KeyWasJustPressed(int key);
 int KeyWasJustReleased(int key);
 
+//---
+// Control systems
+//---
+
+void CGD_Cheat();
+void CGD_SwitchClip();
+void CGD_FreeMem();
+void CGD_CycleFrameskip();
+void CGD_CycleGamma();
+void CGD_ProfilerResults();
+
 //---
 // Performance metrics
 //---
diff --git a/cgdoom/d_main.c b/cgdoom/d_main.c
index 5cd0394..f3394a7 100644
--- a/cgdoom/d_main.c
+++ b/cgdoom/d_main.c
@@ -255,7 +255,7 @@ void D_Display (void)
 //  D_DoomLoop
 //
 extern  boolean  demorecording;
-extern int giRefreshMask;
+
 void D_DoomLoop (void)
 {
   I_InitGraphics ();
@@ -275,11 +275,8 @@ void D_DoomLoop (void)
     gametic++;
 
     // Update display, next frame, with current state
-    if(!(gametic & giRefreshMask))
-    {
+    if(!(gametic % (CGD_Frameskip + 1)))
       D_Display ();
-    }
-
   }
  // I_ShutdownGraphics();
   free(lumpinfo);
diff --git a/cgdoom/doomdef.h b/cgdoom/doomdef.h
index adb37f6..257cec2 100644
--- a/cgdoom/doomdef.h
+++ b/cgdoom/doomdef.h
@@ -304,14 +304,6 @@ typedef enum
 // The utility was written by Dave Taylor.
 //#include "sounds.h"
 
-///
-void CGCheat();
-void CGSwitchClip();
-void CGFreeMem();
-void CGRefreshSwitch();
-void CGCycleGamma();
-void CGProfilerResults();
-
 
 #endif          // __DOOMDEF__
 //-----------------------------------------------------------------------------
diff --git a/cgdoom/i_system.c b/cgdoom/i_system.c
index 32a68d8..f8ca97f 100644
--- a/cgdoom/i_system.c
+++ b/cgdoom/i_system.c
@@ -243,8 +243,6 @@ static void R_SetViewSizeChange(int iDiff)
 
 void I_StartTic (void)
 {
-    extern int giRefreshMask;
-
     //---
     // Rate limiter
     //---
@@ -254,12 +252,12 @@ void I_StartTic (void)
 
     /* Rate limit the game at 35 tics per second, but only extend tics where we
        display frames, because that's when all the work is done */
-    if(!(gametic & giRefreshMask)) {
+    if(!(gametic % (CGD_Frameskip + 1))) {
         if(ratelimit_started) {
             while(1) {
                 prof_t temp = ratelimit_ctx;
                 prof_leave(temp);
-                if(prof_time(temp) >= 28571 * (giRefreshMask + 1)) break;
+                if(prof_time(temp) >= 28571 * (CGD_Frameskip + 1)) break;
             }
             ratelimit_ctx = prof_make();
         }
@@ -288,7 +286,7 @@ void I_StartTic (void)
         if (now == fps_ticks)
             fpscounter_data = -1;
         else
-            fpscounter_data = 128 * fps_frames / ((now - fps_ticks) * (giRefreshMask + 1));
+            fpscounter_data = 128 * fps_frames / ((now - fps_ticks) * (CGD_Frameskip + 1));
 
         fps_ticks = now;
         fps_frames = 0;
@@ -307,21 +305,21 @@ void I_StartTic (void)
     {
         /* Capture events for special keys */
         if(KeyWasJustPressed(SKEY_CHEAT))
-            CGCheat();
+            CGD_Cheat();
         if(KeyWasJustPressed(SKEY_DECVP))
             R_SetViewSizeChange(-1);
         if(KeyWasJustPressed(SKEY_INCVP))
             R_SetViewSizeChange(1);
         if(KeyWasJustPressed(SKEY_NOCLIP))
-            CGSwitchClip();
+            CGD_SwitchClip();
         if(KeyWasJustPressed(SKEY_GAMMA))
-            CGCycleGamma();
+            CGD_CycleGamma();
         if(KeyWasJustPressed(SKEY_FREEMEM))
-            CGFreeMem();
+            CGD_FreeMem();
         if(KeyWasJustPressed(SKEY_FPSCOUNTER))
             fpscounteractive = !fpscounteractive;
         if(KeyWasJustPressed(SKEY_FRAMESKIP))
-            CGRefreshSwitch();
+            CGD_CycleFrameskip();
     }
 
     //---
@@ -341,7 +339,7 @@ void I_StartTic (void)
     else {
         profiler_ticks--;
         if(profiler_ticks == 0) {
-            CGProfilerResults();
+            CGD_ProfilerResults();
             profiler_ticks = -1;
         }
     }
diff --git a/cgdoom/st_stuff.c b/cgdoom/st_stuff.c
index 4ed51c6..f9e7609 100644
--- a/cgdoom/st_stuff.c
+++ b/cgdoom/st_stuff.c
@@ -431,7 +431,7 @@ void ST_refreshBackground(void)
 }
 
 
-void CGCheat()
+void CGD_Cheat()
 {
   int i;
   plyr->cheats ^= CF_GODMODE;
@@ -461,7 +461,7 @@ void CGCheat()
 
 }
 
-void CGSwitchClip()
+void CGD_SwitchClip()
 {
   plyr->cheats ^= CF_NOCLIP;
   if(plyr->cheats & CF_NOCLIP)
@@ -474,7 +474,7 @@ void CGSwitchClip()
   }
 }
 
-void CGFreeMem()
+void CGD_FreeMem()
 {
   static char message[64];
   sprintf(message, "Free: ");
@@ -493,21 +493,16 @@ void CGFreeMem()
   plyr->message = message;
 }
 
-int giRefreshMask = 1;
-void CGRefreshSwitch()
+void CGD_CycleFrameskip()
 {
-  giRefreshMask ^= 2;
-  if(giRefreshMask & 2)
-  {
-    plyr->message = "Fast";
-  }
-  else
-  {
-    plyr->message = "Smooth";
-  }
+  CGD_Frameskip = (CGD_Frameskip + 1) % 4;
+
+  static char message[16];
+  sprintf(message, "Frameskip: %d", CGD_Frameskip);
+  plyr->message = message;
 }
 
-void CGCycleGamma()
+void CGD_CycleGamma()
 {
   extern int usegamma;
   usegamma = (usegamma + 1) % 5;
@@ -517,7 +512,7 @@ void CGCycleGamma()
   plyr->message = gammamsg[usegamma];
 }
 
-void CGProfilerResults()
+void CGD_ProfilerResults()
 {
   static char message[72];
   sprintf(message, "DA:%ums GR:%ums DI:%ums LL:%ums ULL:%ums",