Rocman X (洛克人X) (also known as Thunder Blast Man) is an unlicensed game created by Sachen, released on the Famicom and NES sometime in the 90's and also sometime later for the Game Boy Color. The NES and English Game Boy Color versions were released as Thunder Blast Man, the Chinese version of the GBC game released as 洛克人X金 (Rockman X Gold), and one of the NES versions' label calls it Thunder Blaster Man.

The GBC version has similar graphics and levels, but has completely different music. Most of the graphics are taken from the Famicom version, including some unused enemy graphics. Also, the gameplay is changed to a more traditional Mega Man-styled game and there are no shops or additional weapons in the game.  The level architecture in most of the levels is partially based on the level design from the NES game (usually at the beginning of a stage) although with accommodations made for your character's lack of a fly ability. The bosses require proper timing with hits like the NES version, except they're vulnerable for a much shorter time. Clearing all the stages yields no ending, as the game doesn't record bosses being defeated like a traditional Mega Man game. Two versions of this game exist: A "Rocman X" version featuring slightly edited Mega Man sprites and very slightly lower aim, and the more well-known "Thunder Blast Man" version, featuring the protagonist of the NES game. This version shares numerous similarities with Makon Soft games, particularly Rocman 8 and X4.