Soul: Arrow keys to move. Survive for 8 minutes to win. Sans: Hold Z and press WASD to shoot a small Gaster Blaster in the desired direction. Hold X and press WASD to shoot a large Gaster Blaster. Hold C and press WASD to use bones. Hold V and press WASD to use orange bones. Hold B and press WASD to use blue bones. Press N to turn the soul red, press M to turn it blue. Use F to make a large platform and G to make a small platform. H and WASD to use telekinesis. Press J to enter telekinesis mode. This shrinks the box into a square, and makes it so you can only use Gaster Blasters and telekinesis. If you hold J and use WASD in this mode, you'll use bone zones. Note that you still have to slam the person into the bone zone, so if you use J and H at the same time, it will auto slam them into the bones. Press 1 to use your 5000 KARMA final attack. This will also rapidly heal the soul, but they aren't likely to survive, so you don't need to worry about that. Remember that all attacks take KARMA. Your KARMA will rise over time.
Credit to @loganvcairns for basically all of the assets and base scripts, and of course credit to Toby Fox for making Undertale. Remember, this game is in a very early beta. Many updates are planned. Hope you enjoy!