As the description suggests, so much rage, but really a lot of fun. Those looking for easy medals should look elsewhere, and please consider that this game is *supposed to be hard* before giving it zero stars because "this gam is, lyke, impossbl. I cn't get crustal in lvl 1".
Just a note about dash for those reading this review, you can actually dash (from the ground) in a diagonal by pressing up immediately after pressing x. Though be warned, this does not similarly work when you dash while in the air.
I would also recommend saving your no-checkpoint run for when you're not trying to collect crystals; if you grab a crystal, reach a checkpoint, and die... said crystal is not lost forever. (You have to complete the level with crystal still in your possession to actually "get" the crystal.