Enjoyment: This had that "one more go" kind of hard fun, but having to refresh the browser each time I died kind of killed that. It needs a quick respawn.
Concept: I like the idea of a procedural vertical platformer. It was interesting that you had to platform fast before blocks spawned above and blocked your jumps.
Presentation: Nice tiling texture. A little plain, but I guess the inside of a well would be pretty dull... The depressed froggy thoughts were an interesting touch.
Use of the Limitation: I never made it very high, but I assume there's just the one level?