Aquaman: Battle for Atlantis Unlockables (GameCube)

The dynamic DC Comics super hero stars in a spectacular underwater action/adventure brawler. Aquaman defends the deep-sea city of Atlantis against three of his most infamous arch-enemies, including the Lava Lord and Black Manta. Comic book and video game fans alike will jump at the chance to wield Aquaman's legendary super powers and cybernetic morphing hook hand against these seemingly invincible villains and their armies.

This game has been named "one of the worst games of all time" by the hosts of the show X-Play and was the genesis for their annual "Golden Mullet Awards" - a ranking of the previous years' worst games. Aquaman got revenge for this on their Halloween episode, as he was behind the serial killer "Memory Card" (a spoof of Jigsaw from the Saw movies) and kills many of the G4 staff in the same fashion of Jigsaw. He later realizes the error of his ways, though before he can do anything he is shot dead by two 'policemen'. Though Adam stated in one episode, Drake of the 99 Dragons, "I usually say Aquaman but I hate that game worse", noting a statement during the review of Drake that said it had surpassed Aquaman as the standard by which they judge all future bad games.
(Wikipedia)

Unlockables

Classic Aquaman:
Successfully complete the game under the easy difficulty setting as Aquaman. Classic Aquaman has no Morphing Claw, which means some of his combo moves are not available. However, he swims slightly faster and his telepathy call is different.

Tempest and Black Manta:
Successfully complete the game under the easy difficulty setting as Classic Aquaman. Tempast (Aqualad) has less combos than either Aquaman or Classic Aquaman and no telepathy. However, he has an Ice Beam combo move. Black Manta also has no telepathy power, but has the best combos in the game (some of which require practice). The easiest move to use is the Heat Ray Beam attack or the Grab Heat


Here's a video review of one of the worst games ever developed: