Hey, just reminding you a couple months later to PLEASE add gamepad support! Reflexive gameplay is best suited to gamepads here...
Yk, I am actually a bit curious to know the difficulties in integrating gamepad support here. Realistically, you only need input from 2 things, an analog stick and a button to do anything. (I would prob have to cross-reference between your own player input code and the gamepad documentation for Windows (XInput API) and Linux (Joystick/evdev APIs) to know all of the nuance...)
I did read up on something called SDL_GameController, which should resolve a lot of the problems with supporting multiple controllers, but it is a C-based input library, and I don't know what language Breadskate is developed in