Collect all five hidden keys in the indicated level to unlock the corresponding bonus behind the five-keyed doors.

Effect - Code

2 Turrets - Get all 5 keys in Black Comet
3 Extra lives - Get all 5 keys in The ARK
Alternate path to a red terminal - Get all 5 keys in Mad Matrix
Armored Car - Get all 5 keys in Lost Impact
Black Hawk - Get all 5 keys in Glyphic Canyon
Black Volt - Get all 5 keys in Sky Troops
Extra shooting gallery - Get all 5 keys in Circus Park
Large GUN Cannon - Get all 5 keys in Lethal Highway
Opens cage, which triggers shortcut to the end of the level - Get all 5 keys in The Doom
Shortcut - Get all 5 keys in Cryptic Castle
Switch that makes ring trails to the end of the level - Get all 5 keys in Cosmic Fall
Turrets - Get all 5 keys in Final Haunt
Warp Hole - Get all 5 keys in Death Ruins
Warp Hole - Get all 5 keys in Space Gadget
Warp Portal - Get all 5 keys in The Last Way