#Persistent  ; Keep this script running until the user explicitly exits it.
SetTimer, WatchAxis, 5
JoyStickID = 0
return

WatchAxis:
GetKeyState, %JoyStickID%JoyX, JoyX  ; Get position of X axis.
GetKeyState, %JoyStickID%JoyY, JoyY  ; Get position of Y axis.
KeyToHoldDownPrev = %KeyToHoldDown%  ; Prev now holds the key that was down before (if any).

if JoyX > 70
    KeyToHoldDown = D
else if JoyX < 30
    KeyToHoldDown = A
else if JoyY > 70
    KeyToHoldDown = S
else if JoyY < 30
    KeyToHoldDown = W
else
    KeyToHoldDown =

if KeyToHoldDown = %KeyToHoldDownPrev%  ; The correct key is already down (or no key is needed).
    return  ; Do nothing.

; Otherwise, release the previous key and press down the new key:
SetKeyDelay -1  ; Avoid delays between keystrokes.
if KeyToHoldDownPrev   ; There is a previous key to release.
    Send, {%KeyToHoldDownPrev% up}  ; Release it.
if KeyToHoldDown   ; There is a key to press down.
    Send, {%KeyToHoldDown% down}  ; Press it down.
return