I agree with the other comment, your design for the map was a nice world to explore and the location of the various power-up are very clean so I backtracking doesn't seems stressfull.
An improvement can be the art, it's quite simple, but it's clear so it's your choice for that. Nothing more to say; nice map, clear commands and power-ups, but the player is kinda slow and the lack of musics and various effect don't help the game to outstand.
I got a nice 10 minute to comlete it, and after to try I just launched myself in the void in the dark area, but I had fun to play it