Couldn't get left shift to work either, someone else said to use right shift and I tried it and it worked but the levels were still too hard. The random generation has some flaws for sure but it could work as an endless climber if you refine it. As for positives, the art style is very fitting here! I love the use of negative space. Feels like a game I would play on coolmathgames but in a good way. Like a hidden gem or something