I am sorry for the long wait, irl stuff has gotten to me lately and I haven't been able to code for a long time, so I'll just release this then. You can play this for now. I still have lots of stuff to do >_>
I got some of these mechanic concepts (and some sprites) from other Scratches such as "Memories of the Underground" and "Undertale Boss Fight! On Scratch". Undertale also made by Toby Fox. So I would like to credit them. Other than that, I made this. (links at the bottom.) Notes on Damage: If you get directly hit straight into the Gaster Blaster Beam, then you should take approximately 14 damage. (Not in one hit, but if you stay in the full duration of the blast.) Other attacks only hit you by 1, but you don't receive invincibility frames. (Same goes for the Gaster Blaster.) Why there's no Karmic Retribution: Since you didn't kill any monsters and wanted to train with Sans on your dodging practice, there was no bad deeds you did. That's why there's no Karmic Retribution. (or maybe I'm too lazy to add that ._.) Note: This Scratch is meant to be endless, no ending dialogue or anything. Just a specific goal: try to stay alive as long as possible. And also please tell me if there's any bugs or glitches, I'll try to fix them ASAP! *Remember, I cannot fix ALL bugs that you guys find, I may be stuck on them. So if you guys can help me on certain bugs, please do. It really helps! link to Memories of the Underground: https://scratch.mit.edu/projects/83406592/ link to Undertale Boss Fight! On Scratch: https://scratch.mit.edu/projects/86551446/