wasd/arrows to move. z-select and x-back. It is implied you're already familiar with Undertale's fighting system and this boss in particular. Editing the code can make the game really laggy, just refresh the page. Fullscreen recomended!
Crediit to @MCLTang for original project, I just edited it a lot Here's the update log RELEASE --> Beta 1.0: July 29th 2024 Beta 1.1: August 2nd 2024: Menu redesign, setup to development on the dialogues. Beta 1.2: August 9th 2024: A functioning early dialogue mode(Minimum Viable Version of it) Beta 1.3: August 14th 2024. Now the speech is displayed letter by letter with talking sound effect. Overlall dialogue improvement. Beta 2.0: august 22nd 2024: Items Implemented, as well as the Inventory option in the menu(to edit your items). Version 1.0: march 18th 2025: The fight with dialogues is finished (including all the sequence of sleeping, dodging, actually hitting him, etc...) Version 1.1: April 9th 2025: PLATFROMS finally FIXED when not in full screen mode. Version 1.2: April 10th 2025: Added every remaining item, small changes to the menu. Version 2.0: October 2nd 2025: Hacks were added to make the full experience more accessible. New updates: Version 2.1: Changed bone sprites and menu font to match the normal game, buffed some attacks and updated sound quality