diff --git a/shell/glfw-gamepad.sml b/shell/glfw-gamepad.sml
index d2cbbf8..46ce0fb 100644
--- a/shell/glfw-gamepad.sml
+++ b/shell/glfw-gamepad.sml
@@ -5,7 +5,7 @@ struct
   fun isInDeadZone (x, y) =
     x < 0.1 andalso x > ~0.1 andalso y < 0.1 andalso y > ~0.1
 
-  (* todo: query L2 and R2, and handle them *)
+  (* todo: also query L2 and R2, and handle them *)
   fun axisToDir (x, y) =
     if isInDeadZone (x, y) then CENTRE
     else if abs x > abs y then if x > 0.0 then RIGHT else LEFT
@@ -22,95 +22,144 @@ struct
     orelse Input.getGamepadState 12 <> 0 orelse Input.getGamepadState 13 <> 0
     orelse Input.getGamepadState 14 <> 0 orelse Input.getGamepadState 15 <> 0
 
-  local open InputMsg
-  in
+  local
+    val state =
+      { crossPressed = ref false
+      , circlePressed = ref false
+      , squarePressed = ref false
+      , trianglePressed = ref false
+      , r1Pressed = ref false
+      , l1Pressed = ref false
+      }
+
+    open InputMsg
+
     fun handleTrianglePressed (x, y) =
-      let
-        val chr =
-          case axisToDir (x, y) of
-            CENTRE => #"a"
-          | UP => #"e"
-          | RIGHT => #"i"
-          | DOWN => #"m"
-          | LEFT => #"q"
-          | L2 => #"u"
-          | R2 => #"y"
-      in
-        InputMailbox.append (CHAR_EVENT chr)
-      end
+      if !(#trianglePressed state) then
+        ()
+      else
+        let
+          val () = #trianglePressed state := true
+          val chr =
+            case axisToDir (x, y) of
+              CENTRE => #"a"
+            | UP => #"e"
+            | RIGHT => #"i"
+            | DOWN => #"m"
+            | LEFT => #"q"
+            | L2 => #"u"
+            | R2 => #"y"
+        in
+          InputMailbox.append (CHAR_EVENT chr)
+        end
 
     fun handleCirclePressed (x, y) =
-      let
-        val chr =
-          case axisToDir (x, y) of
-            CENTRE => #"b"
-          | UP => #"f"
-          | RIGHT => #"j"
-          | DOWN => #"n"
-          | LEFT => #"r"
-          | L2 => #"v"
-          | R2 => #"z"
-      in
-        InputMailbox.append (CHAR_EVENT chr)
-      end
+      if !(#circlePressed state) then
+        ()
+      else
+        let
+          val () = #circlePressed state := true
+          val chr =
+            case axisToDir (x, y) of
+              CENTRE => #"b"
+            | UP => #"f"
+            | RIGHT => #"j"
+            | DOWN => #"n"
+            | LEFT => #"r"
+            | L2 => #"v"
+            | R2 => #"z"
+        in
+          InputMailbox.append (CHAR_EVENT chr)
+        end
 
     fun handleCrossPressed (x, y) =
-      case axisToDir (x, y) of
-        CENTRE => InputMailbox.append (CHAR_EVENT #"c")
-      | UP => InputMailbox.append (CHAR_EVENT #"g")
-      | RIGHT => InputMailbox.append (CHAR_EVENT #"k")
-      | DOWN => InputMailbox.append (CHAR_EVENT #"o")
-      | LEFT => InputMailbox.append (CHAR_EVENT #"s")
-      | L2 => InputMailbox.append (CHAR_EVENT #"w")
-      | R2 =>
-          (* todo: either shift or enter *)
-          raise Fail "glfw-gamepad.sml: 77\n"
+      if !(#crossPressed state) then
+        ()
+      else
+        let
+          val () = #crossPressed state := true
+        in
+          case axisToDir (x, y) of
+            CENTRE => InputMailbox.append (CHAR_EVENT #"c")
+          | UP => InputMailbox.append (CHAR_EVENT #"g")
+          | RIGHT => InputMailbox.append (CHAR_EVENT #"k")
+          | DOWN => InputMailbox.append (CHAR_EVENT #"o")
+          | LEFT => InputMailbox.append (CHAR_EVENT #"s")
+          | L2 => InputMailbox.append (CHAR_EVENT #"w")
+          | R2 =>
+              (* todo: either shift or enter *)
+              raise Fail "glfw-gamepad.sml: 77\n"
+        end
 
     fun handleSquarePressed (x, y) =
-      case axisToDir (x, y) of
-        CENTRE => InputMailbox.append (CHAR_EVENT #"d")
-      | UP => InputMailbox.append (CHAR_EVENT #"h")
-      | RIGHT => InputMailbox.append (CHAR_EVENT #"l")
-      | DOWN => InputMailbox.append (CHAR_EVENT #"p")
-      | LEFT => InputMailbox.append (CHAR_EVENT #"t")
-      | L2 => InputMailbox.append (CHAR_EVENT #"x")
-      | R2 =>
-          (* todo: either shift or enter *)
-          raise Fail "glfw-gamepad.sml: 87\n"
-  end
-
-  fun handleIfJoystickIsPresent () =
-    let
-      open InputMsg
-
-      val xAxis = Input.getLeftJoystickXAxisState ()
-      val yAxis = Input.getLeftJoystickYAxisState ()
-
-      val crossPrressed = Input.isCrossButtonPressed ()
-      val circlePressed = Input.isCircleButtonPressed ()
-      val squarePressed = Input.isSquareButtonPressed ()
-      val trianglePressed = Input.isTriangleButtonPressed ()
-
-      val r1Pressed = Input.isR1ButtonPressed ()
-      val l1Pressed = Input.isL1ButtonPressed ()
-    in
-      if crossPrressed <> 0 then
-        (* pressing two buttons at the same time is a no-op *)
-        if
-          circlePressed <> 0 orelse squarePressed <> 0
-          orelse trianglePressed <> 0 orelse r1Pressed <> 0
-          orelse l1Pressed <> 0
-        then ()
-        else handleCrossPressed (xAxis, yAxis)
-      else if circlePressed <> 0 then
-        if
-          squarePressed <> 0 orelse trianglePressed <> 0 orelse r1Pressed <> 0
-          orelse l1Pressed <> 0
-        then ()
-        else handleCirclePressed (xAxis, yAxis)
-      else
+      if !(#squarePressed state) then
         ()
-    end
+      else
+        let
+          val () = #squarePressed state := true
+        in
+          case axisToDir (x, y) of
+            CENTRE => InputMailbox.append (CHAR_EVENT #"d")
+          | UP => InputMailbox.append (CHAR_EVENT #"h")
+          | RIGHT => InputMailbox.append (CHAR_EVENT #"l")
+          | DOWN => InputMailbox.append (CHAR_EVENT #"p")
+          | LEFT => InputMailbox.append (CHAR_EVENT #"t")
+          | L2 => InputMailbox.append (CHAR_EVENT #"x")
+          | R2 =>
+              (* todo: either shift or enter *)
+              raise Fail "glfw-gamepad.sml: 87\n"
+        end
+  in
+    fun handleIfJoystickIsPresent () =
+      let
+        open InputMsg
+
+        (* query possible events for information *)
+        val xAxis = Input.getLeftJoystickXAxisState ()
+        val yAxis = Input.getLeftJoystickYAxisState ()
+
+        val crossPressed = Input.isCrossButtonPressed ()
+        val circlePressed = Input.isCircleButtonPressed ()
+        val squarePressed = Input.isSquareButtonPressed ()
+        val trianglePressed = Input.isTriangleButtonPressed ()
+
+        val r1Pressed = Input.isR1ButtonPressed ()
+        val l1Pressed = Input.isL1ButtonPressed ()
+
+        (* handle button events *)
+        val () =
+          if crossPressed = 0 then #crossPressed state := false
+          else if !(#crossPressed state) then ()
+          else handleCrossPressed (xAxis, yAxis)
+
+        val () =
+          if circlePressed = 0 then #circlePressed state := false
+          else if !(#circlePressed state) then ()
+          else handleCirclePressed (xAxis, yAxis)
+
+        val () =
+          if squarePressed = 0 then #squarePressed state := false
+          else if !(#squarePressed state) then ()
+          else handleSquarePressed (xAxis, yAxis)
+
+        val () =
+          if trianglePressed = 0 then #trianglePressed state := false
+          else if !(#trianglePressed state) then ()
+          else handleTrianglePressed (xAxis, yAxis)
+
+        val () =
+          if r1Pressed = 0 then #r1Pressed state := false
+          else if !(#r1Pressed state) then ()
+          else InputMailbox.append (CHAR_EVENT #" ")
+
+        val () =
+          if l1Pressed = 0 then #l1Pressed state := false
+          else if !(#l1Pressed state) then ()
+          else InputMailbox.append KEY_BACKSPACE
+      in
+        ()
+      end
+  end
 
   fun query () =
     if getGamepadState () then handleIfJoystickIsPresent ()