Rockman DX3, also known as Zook Hero 2, is an an unlicensed pirate game developed by Vast Fame that rips gameplay off the Rockman X series. Just like Rockman X, there are eight stages, and six of them contain a boss who gives you his weapon upon defeat. The protagonist, Zook, also has abilities nearly identical to those of X. Despite these similarities, the code and graphics appear to be completely original and the music is actually decent.
Unlike the other run of this game, this run uses a release that doesn't have all stages unlocked from the start, which means all bosses must be defeated and all upgrades obtained first before Zook can tackle the final stages.
We also have a run of this game's prequel, Zook Hero Z.