Thanks for the feedback! The dark room people seem to getting stuck in is the final area. There is a closed door that needs to be shot after getting a weapon upgrade from the Rhino boss. I had hoped to do more to guide the player to the feeling of solving this on their own but I think maybe an introspective dialogue box from our hero mentioning that it's weapon isn't powerful enough yet.
I totally get your points about the level design, We had attempted to do some more ambitious things with the levels involving some more movement based platforming but with the holidays we ran out of time to implement it and had to pivot to finish in time.
Thanks for playing :)