diff --git a/gameconfig.lua b/gameconfig.lua
index 775cae7..4a43622 100644
--- a/gameconfig.lua
+++ b/gameconfig.lua
@@ -1,6 +1,26 @@
 -- "gameconfig" is kind of a misnomer, to be honest.
 -- it's more like things the end user shouldn't have to change.
 
+local function jp_buttons(s)
+    s = string.lower(s or "")
+    local t = {
+        up     = false, down   = false, left   = false, right  = false,
+        select = false, start  = false, B      = false, A      = false,
+    }
+    for w in s:gmatch("%a+") do
+        if w == 'up' then t.up = true
+        elseif w == 'down' then t.down = true
+        elseif w == 'left' then t.left = true
+        elseif w == 'right' then t.right = true
+        elseif w == 'select' then t.select = true
+        elseif w == 'start' then t.start = true
+        elseif w == 'a' then t.A = true
+        elseif w == 'b' then t.B = true
+        else error(("unknown button: %s"):format(w)) end
+    end
+    return t
+end
+
 local gcfg = {
     input_size = 60 + 4, -- TODO: let the script figure this out for us.
     tile_count = 17 * 13,
@@ -25,46 +45,19 @@ local gcfg = {
     },
 
     jp_lut = {
-        { -- none
-            up     = false, down   = false, left   = false, right  = false,
-            select = false, start  = false, B      = false, A      = false,
-        }, { -- A
-            up     = false, down   = false, left   = false, right  = false,
-            select = false, start  = false, B      = false, A      = true,
-        }, { -- L
-            up     = false, down   = false, left   = true,  right  = false,
-            select = false, start  = false, B      = false, A      = false,
-        }, { -- R
-            up     = false, down   = false, left   = false, right  = true,
-            select = false, start  = false, B      = false, A      = false,
-        }, { -- L + B
-            up     = false, down   = false, left   = true,  right  = false,
-            select = false, start  = false, B      = true,  A      = false,
-        }, { -- R + B
-            up     = false, down   = false, left   = false, right  = true,
-            select = false, start  = false, B      = true,  A      = false,
-        }, { -- L + A
-            up     = false, down   = false, left   = true,  right  = false,
-            select = false, start  = false, B      = false, A      = true,
-        }, { -- R + A
-            up     = false, down   = false, left   = false, right  = true,
-            select = false, start  = false, B      = false, A      = true,
-        }, { -- L + A + B
-            up     = false, down   = false, left   = true,  right  = false,
-            select = false, start  = false, B      = true,  A      = true,
-        }, { -- R + A + B
-            up     = false, down   = false, left   = false, right  = true,
-            select = false, start  = false, B      = true,  A      = true,
-        }, { -- D
-            up     = false, down   = true,  left   = false, right  = false,
-            select = false, start  = false, B      = false, A      = false,
-        }, { -- D + A
-            up     = false, down   = true,  left   = false, right  = false,
-            select = false, start  = false, B      = false, A      = true,
-        }, { -- U
-            up     = true,  down   = false, left   = false, right  = false,
-            select = false, start  = false, B      = false, A      = false,
-        },
+        jp_buttons(),
+        jp_buttons("a"),
+        jp_buttons("left"),
+        jp_buttons("right"),
+        jp_buttons("b left"),
+        jp_buttons("b right"),
+        jp_buttons("a left"),
+        jp_buttons("a right"),
+        jp_buttons("b a left"),
+        jp_buttons("b a right"),
+        jp_buttons("down"),
+        jp_buttons("a down"),
+        jp_buttons("up"),
     },
 }