here's my thoughts: (sorry im about to go to bed so I'm being brief)
I didn't understand the differences between all the materials. ok some are stronger than others, but I really think you could boil it down to 3 at most- weak medium strong for example
I noticed some stages didn't give you any materials? I think each and every stage should have a puzzle about where to put blocks, and ideally not just one solution.
I felt some levels I could get the switches quick then I had to spend a long time hiding from bullets.. I reckon it should be more like, once you have the radio on stay alive another 10 seconds or something, rather than 40 in some cases
it's not obvious at first that you'll pass straight through the switch and radio blocks. they look like solid blocks
winning or losing the level should probably take you back to level select, not the splash screen
at least 1 more music track would be appreciated, so you can alternate music between levels and get a bit of variety
. I like the track it just gets samey
if I think of anything more I'll come back tomorrow
I think all the elements of a good game are in place, they just need some tweaking and streamlining. nice one!
PS, i know it's built to support a joystick, but adding mouse support would really speed things up- it's just the easiest way to use an editor like that. I'm sure you could have it work both ways.