Wow, Surprisingly inventive. For such a simple setup, you managed to do a lot with it.
I think every single level here is unique, The aesthetics are... Not the best, I see sometimes pixels going over black lines, and some characters just look sloppy. Definitely not bad, but I've seen better. Sound is simple, pretty much all you need while you're trying to think.
The level design is.. pretty incredible, I like how creative each level was. I occasionally found myself just clicking around rather then actually thinking, on the second gas mask level for example. The only levels I think I would complain about is the math guardian one, the two being a different color threw me off for a while from the real solution, and the "Don't touch me".
I admit, I did overthink it, it's as simple as arranging them so they don't touch, but for some reason it took me very long to do so. I will say the twist on the "Spot the difference" was one i've seen before, but good try.
Story was extremely simple, a bit strange in some parts, but I think it's a fairly challenging, overall well made puzzle game. Good work.