I like it! I think it's cool you managed to get so much content out of just a few mechanics. The difficulty ramps up very quickly, but the mechanics are very easy to get to grips with!
I think gameplay wise one of my only concerns would be that some levels take a very long time, or look very intimidating from the beginning which may dissuade people from playing to completion. This is always something to be wary of in single-screen puzzles. Especially where failure resets the whole thing. My own entry is guilty of this sometimes as well.
I think you focused on the right things, and 'did what you could' with the presentation to give it a neat aesthetic despite obviously being very simple. Always the wise choice if you're not artistically confident.
Simple but powerful, you made real intersting level but maybe you could imagine a morepregressive way. The black and white style is intersting but the graphics and the font could be maybe better to create a more trendy look, more classic.
Actually some level are maybe too scary for a free game, even if there is a solution...
At the end i'm always impressed by puzzle design and here it's well done even with hard puzzle... the hardest to design ;)
I think gameplay wise one of my only concerns would be that some levels take a very long time, or look very intimidating from the beginning which may dissuade people from playing to completion. This is always something to be wary of in single-screen puzzles. Especially where failure resets the whole thing. My own entry is guilty of this sometimes as well.
I think you focused on the right things, and 'did what you could' with the presentation to give it a neat aesthetic despite obviously being very simple. Always the wise choice if you're not artistically confident.
Good stuff!