Got stuck in the level where input is > < and expected output is ^^. I accidentally deleted the splitter though, and then couldn't get it back, so if it was needed in this level, it would explain a lot.
I love the concept, some of the levels I last played were great and the difficulty curve felt okay so far. In my own games, I usually follow a very difficult level up with a couple of easier levels, not like stupid easy levels, but less difficult than the very difficult level was. This way there is a "reward" for beating the very difficult level: you can now make some actual progress instead of getting stuck in the next level, while every level is still challenging enough to be interesting and while the game is progressively getting more and more difficult. Not everyone likes this kind of game design, but I do - though, I also often have action elements in my puzzle games which makes them fundamentally a bit different from this game, so I'm not even sure how well it would work here. But at least it's an idea, if not one worth implementing.
