Good retro-themed game, but too weird on gamepad controls. You really should have let people remap gamepad buttons. It would not have been hard to add a gamepad config screen and let players map the buttons as they wish.
Here is how it plays if you use a Playstation 3 controller. Left joystick moves, okay fair enough. D-pad left or D-pad right is jump as well as accepts menu selections = totally unacceptable! Square button is fire, okay, but not when jump is D-pad left or right, lol. I guess Playstation 3 controller users are supposed to be mutants with two left thumbs.
How it should have played on such controller. Left joystick *or* D-pad moves. Square button as fire, X button as jump *or* the reverse of that.
Recommended to play using a keyboard only unless your *exact* gamepad is the XBox 360 gamepad, in which I assume it is okay, though I don't have one of those to verify personally. There was precisely zero good reason for this arbitrary oversight as a simple config screen would have allowed *any* gamepad to work well provided the browser can interact with it.