There are four options at the bottom of the screen when you meet an enemy, which are FIGHT,ACT,ITEM,and MERCY.
Fight allows you to attack to it.
Act allows you to select actions. After selecting, the monster will make the corresponding response, with text or pictures displayed in the dialog box on the top, where the Attack point and the Def point would also be shown.
Item allows you to choose items in a battle.
Mercy allows you to flee or spare the life of the monster, when its name turns yellow.
The player should try to avoid the rain of bullets released by the enemy in a specific amount of time, and the player's HP will decrease when hit.
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Long ago, two races ruled over Earth: HUMANS and MONSTERS.
One day, a war broke out between the two races.
After a long battle, the humans won and sealed the monsters underground with a magic spell.
Soundtrack
Undertale's soundtrack album starts on sale on September 15, 2015.
The Neutral Route(NE)is the most chosen for the primary route for players, whose final boss is the Photoshop Flowey. You can only fight him once unless a True Reset or a Genocide Route is done.
The True Pacifist Route (PE) leads to the true endings of the game. The final boss is Asriel.
The Genocide Route (GE) is the route when you kill every possible monster in the Underground. The final boss is Sans.