Take on Jevil and Spamton NEO in a lightweight browser battle simulator. It recreates the turn-based rhythm of DELTARUNE: FIGHT to deal damage, ACT to weaken the boss, ITEM to heal, DODGE to soften the next hit, and SPARE to try for a mercy ending. No download — just pick a boss and fight.
Pick a move. The fight only ends one of two ways.
The simulator mirrors DELTARUNE's rhythm: every action you take is followed by a boss turn. Damage is calculated from attack and defense stats, ACT moves change the boss's stats, and SPARE only works once a boss is weak enough. Beat a boss by emptying its HP, or spare it for a mercy ending — both are real win conditions, just like in the game.