O.K, so, there are a number of options:* There's a bug in Lime (well, SDL really) when you enable vsync (it's on by default in your project.xml) on an Intel HD Graphics (4400/4600 for example). So, the "solution" here is to disable vsync (="false"). There are a number of other Lime/OpenFL bugs that can be responsible, but let's not go there yet.
* Debug: It's really easy - you build in debug mode, press "
`" if the debug windows didn't show, and then press on the brush symbol in the upper (your) right corner. Navigate through the bitmaps to check if there is a bitmap which is much larger than the game's window (tilemaps can cause that sometimes).
* hxscout: Check out the example I gave if you have any problems (don't forget to add the "telemetry" flag to your project.xml). This is really meant for you to double-check your code, as there are many many ways you could've caused it yourself (again, mostly related to your tilemap). A simple project or some code+an asset to demonstrate your problem would be helpful here.
* The Gamepad part sounds weird, I want to say a bug, but maybe your Gamepad is just not supported (what kind is it?). Maybe you can try updating the gamepad's values based on these:
https://github.com/HaxeFlixel/flixel/tree/dev/flixel/input/gamepad/id. If all things fail, open an issue on Github (
https://github.com/HaxeFlixel/flixel/tree/dev).