Each hero has one attack key, from left to right: Q, W, O, P.
Healthbar is actually presenting also your attack range. You must attack the boss in a moment, when timeline is in your attack range, however beware of attacking in the moment, when the timeline is also in the attack range of the boss! In that case, you hero will receive a damage instead!
Game is ready to scale with more heroes and more bosses at the same time. It is prepared for touch devices as well. Written in P5.js framework with target framerate 60 fps.