The following are unlocked in stages by collecting ALL 5 keys and then unlocking the corresponding 5-keyed door.

Unlock 3 Extra Lives:
In The Ark get ALL 5 keys

Unlock 2 Turrets:
In Black Comet find ALL 5 keys

Unlock Turrets:
In Final Haunt find ALL 5 keys

Unlock Armored Car:
In Lost Impact find ALL 5 keys

Unlock Black Volt:
In Sky Troops find ALL 5 keys

Unlock Warp Hole:
In Death Ruins find ALL 5 keys

Unlock Warp Hole:
In Space Gadget find ALL 5 keys

UnWarp Portal:
In The Last Way find ALL 5 keys

Unlock Shortcut:
In Cryptic Castle find ALL 5 keys

Unlock Black Hawk:
In Glyphic Canyon find ALL 5 keys

Unlock Air Saucer:
In Lava Shelter find ALL 5 keys

Unlock Air Saucer:
In Central City find ALL 5 keys

Unlock An Air Saucer:
In Air Fleet find ALL 5 keys

Unlock Armoured car:
In Westopolis find ALL 5 keys

Unlock GUN Vehicle:
In Lost Impact find ALL 5 keys

Unlock Milatary Vehicle:
In GUN Fortress find ALL 5 keys

Unlock Tank Cannon:
In Prison Island find ALL 5 keys

Unlock Tank cannon:
In Iron Jungle find ALL 5 keys

Unlock Black Arm's Vehicle:
In Sky Troops find ALL 5 keys

Unlock Black Arm's Vehicle:
In Glyphic Canyon find ALL 5 keys

Unlock Large GUN Cannon:
In Lethal Highway find ALL 5 keys

Unlock Warp Hole:
In Digital Circuit find ALL 5 keys

Unlock Extra shooting gallery:
In Circus Park find ALL 5 keys

Unlock Alternate path to a Red Terminal:
In Mad Matrix find ALL 5 keys

Unlock Switch that makes Ring Trails to the end of the Level:
In Cosmic Fall find ALL 5 keys

Opens Cage which triggers Shortcut to the end of the Level:
In The Doom find ALL 5 keys

Unlock 'Last Story':
Beat all of the story lines Hero and Dark Endings (10 in total)

Unlock Level 2 Weapons:
When you have beaten the Hero and Dark sides of a story line you will then get your weapon upgraded to level two

Unlock Expert Mode:
Get all 71 "A" rankings.


Library Cutscenes

216 - At vagrancy's End:
1 Nuetral, 1 Hero, 3 Nuetral then Hero

230 - The Ultimate Choice:
Neutral, Hero, Hero, Neutral, Dark then Hero

262 - Steel Combat Boots:
1 Hero, 1 Dark, 1 Nuetral, 1 Hero, 1 Dark then Dark

276 - The Dark Part Of The Galaxy:
Hero, Dark, Hero, Neutral, Neutral then Hero

316 - The One Who Maria Entrusted:
3 Hero, Neutral then Hero till the end

321 - Sparks On The Horizon:
3 Hero, 1 Dark, 1 Hero then Dark

322 - A Use for a Saved Life:
Dark, Neutral, Dark, Hero then Dark

323 - Coffin of Memories:
Hero, Neutral, Hero, Neutral, Dark then Dark

324 - The Self-Imposed Seal:
First 4 Hero missions, Neutral then Hero

325 - A Missive From 50 Years Ago:
First 5 Hero missions then Dark for the final one

326 - Pretense in the Mirror:
6 Hero missions, Hero final boss


Secret weapons:
Beat a story line to a weapon then break open the Shadow Head box to use it

Egg Vaccum:
Beat Normal Story line

Heal Cannon:
Beat Full Hero Story line

Omochao Gun:
Beat Semi Hero Story line

Satellite Laser:
Beat Semi Dark Story line

Samurai Blade:
Beat Full Dark Story line

Shadw Rifle:
Get ALL Endings then complete 'Last Story'