Cheating at games is nothing new. But we can be more creative than, say, simple invincibility. Take this version of the classic title Pac-Man by Shaun Williams, which lets you see the ghost's pathing mechanic in real-time as you smash down those delicious yellow dots.
Bundled together with several standard cheats, Williams' game also allows you to turn on paths and targets for the ghosts. Along with being plain interesting, it adds a strange dimension to the game -- even with your new precognitive abilities, you can still be killed and in fact, it makes you take less risks than you normally would.
It's a neat diversion and a great way to get some insight into how these old-school "basic" games managed to be tense while still having some randomness.
If you're wondering how it was put together, Williams has an extensive breakdown of all the features and mechanics crammed into the game. You might be surprised at exactly how much content there is.