I'm gonna start with a really small detail that I think shows the care on this.. the way the game-palette colour matches the colour of the game-page so it looks seamless; that was the first impression and immediately I thought "oh this is gonna be a good'un".
And whad'ya know, it absolutely was! Crazy smart conceptually having the countdown relate to an uncontrollable input timing, not seen anything quite like it. Gave a really nice tempo to the levels and whilst it was difficult, I felt the way the pointer sort-of lazily "floats" in the direction you point it felt very.. well.. jellyfish! The challenge was made a lot fairer too by the way the health resets and especially liked how being damaged allowed you to stop and take a breather. It was the little balances that made me keep picking it up after copping it.
Stylistically awesome too, the little outline on the player and the background and movement effects were on-point, palette choice is sublime.
Absolutely loved it!