The background is interesting and charming. Too bad there's no context that brings the whole universe.
There's a tuto in the beginning that show us the mapping and that's useful and well done. It just lack a bit of explanation of the game mechanics. But everything becomes clear really easily.
The game is quite accessible in the beginning, but suddenly it becomes a "Die and retry" and god it's hard if you don't pick up all the power up.
At least there is some checkpoints to balance everything. (You should put one next to the toothed wheel)
The SFX is great and the music of the menu is awesome. The other ones are monochord and quite low in the mix. It gives an impression of background noise that does not pay tribute to the generative music system of the game. However that point is understandable due to the duration of the JAM.
Some pattern of monsters are really ingenious. The one that's teleporting needs a sign or a SFX that show us he's dealing damage, that's not really clear in the game.
This game is a must try. Except some default which are imputed to the JAM, that game really really deserve attention.