X/X4/Beta/

The 8 Mavericks
Fortress Bosses
Subbosses
Intro Boss
Enemies
Weapons
Ride Armor
Miscellaneous
Unused Sprites
Rockman X4 Beta
X4 Prototype Sprites
Beta Zero
Other

Recently, a Prototype copy of Rockman X4 was leaked onto the net.
It contained several unused and alternate animations for Zero, not found in the retail version of the game.