hello,
i am one of the moderator of the DD section. Finalizagames pointed me out this. 
I am not DD master system specialist, and do not know if it can be considered as a cheat. It does seem that his WR is run on Master System original software though, but there is nor formal proof.

If you and other runners of this version can define it is a cheat, please let me know and we will delete accordingly.

Double Dragon (master system)