GunLord/Secrets & Mysteries

Secrets
Secret Ending There is a secret ending cutscene. To see it you have to finish the game with all 54 Big Diamonds collected (1 Credit Clear isn't required). By the way you can skip ending and staff screens by pressing A B and C at the same time.

Mysteries

 * Oddly, all the letters in the game are in caps except the "i"...
 * The smart bombs have 3 different official names : Silent Flash, Super Wave and Side Blast...
 * In stage 1, just after the first climbing wall there are 4 red enemies on the ceiling. This ceiling is climbable too but it is not glowing blue like all the others...
 * In stage 3, before the first boss there is a room filled with poisonous water and a Power Shot item just under the ceiling. There are no known way to get it, except by luring a flying enemy from really far away (about 1 minute of careful travel with it to not lose or destroy it) and bouncing on it. It's probably a level design forgetting...