You only have 20 as your maximum HP, so use it wisely! Also, your Soul is normally red, but if the enemy changes it to blue, you will sink to the bottom of the box so you'll have to jump to avoid attacks. If you touch a blue attack, you have to be still! Or else, you'll take damage! But! If you touch a white attack from the second player, you will take damage no matter what.

This damage the enemy and once they run out of HP, the Soul 'wins!' Player 2, of course gets to attack as well. Normally the FIGHT button will be grey but once it charges up, you can press Z to attack! Right, so you control your Soul with arrow keys.

Welcome to the 2 player, extra extraordinary Undertale battle simulator, Undersim! Upon being greeted, you will be able to choose from a variety of different battles that you may or may not have played before! This game may contain spoilers so, go COMPLETE UNDERTALE!

NOTE: This game is being actively developed in Scratch and more boss battles and features are being added all the time.

Gamejolt undertale sans simulator