Fun game, little short but its a game jam so its all good :). On my frist playthrough i did play slowly, didnt spam the attack button and killed fish within 2 phases of sleep and he should go through 3, on the 2nd playthrough i spammed and killed the fish on frist phase of sleep. Bloop is actually kinda difficult until you get hang of it. You will maybe die few times which is fine and it should be like that.
I think one more boss would be perfect but devs were probably limited on time so its all good.