Could use a slower ram up in challenge with mechanics being introduction being more spread out. Overwise great cone game loop. My advice is to try and make you game (at the beginning at lest) too easy for you, You've likely tested the level over and over and you know exactly how the mechanic work so you actually have a huge advantage over someone trying it for the first time. In my game i keep making it easier and easier and what I finally posted I though was very easy but most of the comments in that regard talk about how chalganing (but fair) the game was. Never underestimate play test with new players. even a little can be really helpful