Thanks for playing a providing feedback! Dying in this game is based on two factors: your insanity bar, and the dead flowers that you have(my dumb self should've stated this about the flowers). If all of your flowers die you automatically lose. In hindsight, I made the shark hitboxes too small. I tried to make the tutorial short and to the point. I'll work on making better tutorials in the future.
Once again, thanks for playing!