A few criticisms.
1: Being able to freely reset any level consequence free. The player needs some penalty for ultimate death - whether it's a score reduction or an amount of lives independent of the amount of guesses.
2: Button lag. This happens sometimes for me on flash games, but it was especially bad here. I'd press a button, it'd get "stuck" within the game, and I'd be forced to watch myself helplessly plummet off an edge.
3: If the block you spawn on is somehow removed, you will plummet into the abyss helplessly. My recommended remedy is a "frozen" player on spawn, affected by gravity only after the player moves first. This flaw didn't come up too often (and when it did, it was intentional), but it's things like this that make the game more professional and better.
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