I Wanna Be the Guy is a free indie performer game created and designed by Michael "Kayin" O'Reilly. The whole game is near-impossibly difficult, and parodies popular games from the 8-bit era. In fact most of the games levels, characters, music, sound effects, and more are taken directly from other games.
Some games from which I Wanna Be the Guy has appropriated assets from are:
The game's plot is told through cryptic and poorly written text during the games opening credits, satirizing the often clumsy translations from early 8-bit games. The opening credits parody the opening credits from The Legend of Zelda. The player is "The Kid" who is on a quest to kill "The Guy" so that he can become The Guy.
"The Kid" controls very much like a standard twitch shooter-platformer. He can move left and right, turn in midair without horizontal momentum, jump (and double-jump), and shoot. Even the start screen parodies the one from Mega Man 2. The only 'power-ups' to be found in the game, however, are minor upgrades to the "very small gun" carried by the player character - such as one extra bullet on the screen at a time, a slightly increased range, etc. The player must get past each 'screen', some of which have multiple exits, to progress further in the level. Almost all objects, characters, enemies and sometimes even the environments themselves are designed to surprise and kill the player and make it nearly impossible to proceed.
An absurd amount of precision and timing is required, and even seasoned gamers will find themselves dying multiple times on every screen of the game, especially as the game plays with player expectations; just because the last three platforms fell when you stepped on them doesn't mean the fourth won't move upward the moment you land on it, propelling you into the spikes just above you.
At the end of each level is a boss, which is usually some sort of altered or hybrid of bosses from popular 8-bit games such as Mecha Birdo and a giant Mike Tyson. Each boss has multiple attack patterns that come into play as it takes damage, with the sole exception of Mother Brain - which behaves essentially the same as in the original Metroid game, except each of the flying projectiles are instantly deadly.
I Wanna Be The Guy is available for free from its creators site: http://kayin.pyoko.org/iwbtg/