the idea of this is great. it feels like the introduction to a much bigger game with ever growing mechanics. I pretty much agree with derpy on all accounts though. If you were to scale things back some at the start and work your way up after awhile and introduce some new mechanics and/or enemy spawns then this could really be something.
actually, after looking at the screenshots i'm gonna keep going cause it looks like thats the case.
so i think really if you just increased the coin drops to something like x10-30 then you'd be good. the progression seems fine, its just nearly impossible to reach stuff with the current rates. even the hitbox sizes could be overlooked due to having the spike traps, if they could be purchased and upgraded in a reasonable amount of time.