Press space instead of Z to select. Say "KittyTale" in comments if you remixed and posted it.
Ayy mates I made my own Simple UnderTale Battle Creater! It's super easy to use! Step 1.) Remix this project. Step 2.) Change the messages or text letters. Step 3.) Upload/Make your own battle sprite. (Optional Step. Edit the attack sprites) This is still WIP because I am trying to add more attacks but the only attacks I know how to program is those dots ones.