The premise is interesting but the execution is spotty. The spikes feel haphazardly placed and the levels don't take advantage of the premise that much. The dash upgrade shoots the player way too far and feels unwieldy to use. I like the idea of having earlier playthroughs being times to gather coins for the upgrades later as the time ticks down and makes playing through it more demanding. I agree with Goat dog that buying time can trivialize the game. You don't usually need it though as the levels are simple enough to get through within the time limit anyway.