Yeah, I agree it is not necessary at all for the game to be fast paced. For the puzzle difficulty, I think it has a pretty good balance of difficulty, not too hard to where it takes too long to figure out making it repetitive, but not too easy where not much thinking is involved. I really liked the challenge of chapter 4 the most, since I liked the mechanics of having 3 blocks instead of 2 which gives it a nice difficulty boost for the final few levels. It took me about a hour and a half to complete, although I was going for the bonus parts which contain the little white dot things to collect too on almost every level so it probably took longer doing that also, but I don't think the length of the levels or game is a problem at all. Can't wait to play the completed version!