Blue attacks mean you have to stop, orange means you have to move through them. Use z to select and x to cancel. Use the arrow keys to navigate during attacks and when you are in the menu. You can spare or kill, the choice is yours. :) I would recommend playing in smallscreen with Firefox in order to boost the experience, as fullscreen distorts the sprites, and Firefox runs better than something like Google Chrome
Toby Fox for Undertale, and my friend Leo for this idea. I would link his YouTube channel, but he always deletes it lol. And Tazmi on Soundcloud for the new Bonetrousle theme. Credit to loganvcairns for the phase mechanics. He is a really great coder and sprite maker, so please check him out! Here is a link to his account! https://scratch.mit.edu/users/loganvcairns/ And the biggest credit of all goes to pococikapusta for making the Undertale Battle Creator!