Music credits:
Undertale OST: 051 - Another Medium by Toby Fox
Undertale OST: 065 - CORE by Toby Fox
gmtn (witch's slave) - furioso melodia
Destroid - Annihilate
Undertale - Dummy! - Remix by Emdasche
Dungeon-style/Boss Blitz type game. Very detailed (artwork) and very difficult!
Normal Ending Tutorial:
Play though game normally. Go through center door in 3rd level.
Secret Ending Tutorial:
Collect armor key left of toilet in 1st level. Then go through the secret wall in second level and touch chest, which spawns the armor (+30 hp boost, helpful for normal boss too). Destroy the wall with the armor icon on it and touch the glitch. glitch will allow you to enter the secret boss fight. (Note that you can enter the area of the secret boss portal through the glitched wall in 3rd level, just that you cannot enter the portal without the glitch.)
Storyline: Meet Prototype, a rejected robot looking for revenge upon his creators for rejecting him, and hopefully escape the facility in the process. As he hunts for the mastermind of the facility, he realizes that the one at the top is just a puppet, in control of something much larger than the facility...