Pwn Adventure Z is a Zelda-like game featuring zombies, originally created for a "capture the flag" hacking competition. As such, it contains various intentional glitches and intentionally unfixed glitches that can be exploited for a fast completion.
This movie ignores all the intended glitches in favor of using save corruption to go out of bounds and defeat a duplicate copy of the final boss, thus skipping basically all the intended and intentionally-glitched gameplay of the game.
You can watch this run being played back on a real console.