diff --git a/libretro/libretro.cpp b/libretro/libretro.cpp
index 42e06322..9c5bb99f 100644
--- a/libretro/libretro.cpp
+++ b/libretro/libretro.cpp
@@ -63,21 +63,21 @@ void retro_set_environment(retro_environment_t cb)
       // These variable names and possible values constitute an ABI with ZMZ (ZSNES Libretro player).
       // Changing "Show layer 1" is fine, but don't change "layer_1"/etc or the Yes|No ones.
       // Adding more variables and rearranging them is safe.
-      { "layer_1", "Show layer 1; Yes|No" },
-      { "layer_2", "Show layer 2; Yes|No" },
-      { "layer_3", "Show layer 3; Yes|No" },
-      { "layer_4", "Show layer 4; Yes|No" },
-      { "layer_5", "Show sprite layer; Yes|No" },
-      { "gfx_clip", "Enable graphic clip windows; Yes|No" },
-      { "gfx_transp", "Enable transparency effects; Yes|No" },
-      { "sndchan_1", "Enable sound channel 1; Yes|No" },
-      { "sndchan_2", "Enable sound channel 2; Yes|No" },
-      { "sndchan_3", "Enable sound channel 3; Yes|No" },
-      { "sndchan_4", "Enable sound channel 4; Yes|No" },
-      { "sndchan_5", "Enable sound channel 5; Yes|No" },
-      { "sndchan_6", "Enable sound channel 6; Yes|No" },
-      { "sndchan_7", "Enable sound channel 7; Yes|No" },
-      { "sndchan_8", "Enable sound channel 8; Yes|No" },
+      { "s9x_layer_1", "Show layer 1; Yes|No" },
+      { "s9x_layer_2", "Show layer 2; Yes|No" },
+      { "s9x_layer_3", "Show layer 3; Yes|No" },
+      { "s9x_layer_4", "Show layer 4; Yes|No" },
+      { "s9x_layer_5", "Show sprite layer; Yes|No" },
+      { "s9x_gfx_clip", "Enable graphic clip windows; Yes|No" },
+      { "s9x_gfx_transp", "Enable transparency effects; Yes|No" },
+      { "s9x_sndchan_1", "Enable sound channel 1; Yes|No" },
+      { "s9x_sndchan_2", "Enable sound channel 2; Yes|No" },
+      { "s9x_sndchan_3", "Enable sound channel 3; Yes|No" },
+      { "s9x_sndchan_4", "Enable sound channel 4; Yes|No" },
+      { "s9x_sndchan_5", "Enable sound channel 5; Yes|No" },
+      { "s9x_sndchan_6", "Enable sound channel 6; Yes|No" },
+      { "s9x_sndchan_7", "Enable sound channel 7; Yes|No" },
+      { "s9x_sndchan_8", "Enable sound channel 8; Yes|No" },
       { NULL, NULL },
    };
    
@@ -86,37 +86,37 @@ void retro_set_environment(retro_environment_t cb)
 
 static void update_variables(void)
 {
-   char key[10];
+   char key[14];
    struct retro_variable var;
    
    var.key=key;
    
    int disabled_channels=0;
-   strcpy(key, "sndchan_x");
+   strcpy(key, "s9x_sndchan_x");
    for (int i=0;i<8;i++)
    {
-      key[8]='1'+i;
+      key[strlen("s9x_sndchan_")]='1'+i;
       var.value=NULL;
       if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value && var.value[0]=='N') disabled_channels|=1<<i;
    }
    S9xSetSoundControl(disabled_channels^0xFF);
    
    int disabled_layers=0;
-   strcpy(key, "layer_x");
+   strcpy(key, "s9x_layer_x");
    for (int i=0;i<5;i++)
    {
-      key[6]='1'+i;
+      key[strlen("s9x_layer_")]='1'+i;
       var.value=NULL;
       if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value && var.value[0]=='N') disabled_layers|=1<<i;
    }
    Settings.BG_Forced=disabled_layers;
    
    //for some reason, Transparency seems to control both the fixed color and the windowing registers?
-   var.key="gfx_clip";
+   var.key="s9x_gfx_clip";
    var.value=NULL;
    Settings.DisableGraphicWindows=(environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value && var.value[0]=='N');
    
-   var.key="gfx_transp";
+   var.key="s9x_gfx_transp";
    var.value=NULL;
    Settings.Transparency=!(environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value && var.value[0]=='N');
 }