For the controls, looking back it, after a couple of days out of the game: they are difficult to see at first glance, every binds (beside the repo bind which indeed cannot be changed in this version) works perfectly for me (even after being rebinded), the intent behind letting the player switch keys was to let them play with their favorite keys layout (maybe they like all game keys close to each other, maybe they like to have them far apart, etc).
For the game goals (as stated in the game description): you need to gather resources (with your gun) to repair your mech and re-establish contact with the outside world, you can view and be reminded of the objectives by popping the escape menu and click the help section, now I did thought after submitting the game that it lacked a bit of explanation (which I added further down the game page) but since I didn't know if we were allowed to modify after submitting, I left my game build unchanged.
Sorry for the inconveniences and thank you for playing !