Sorry for taking so long to add such an essential functionality.
Problem is, it took me some time to realize many players didn't have (or simply didn't want to use) a Xbox-compatible controller to play the game. So, here it is:
[b]WASD or arrow keys:[/b] movement / menu navigation
[b]Spacebar:[/b] fire / OK
[b]M or ESC:[/b] boost / Cancel
[b]< and >:[/b] change weapon