"Only original games allowed, no fan games, no remakes, demakes or romhacks. It's simple. No copyright violation!" If I have permission from the original game author will it be eligible to participate?
If it's a 1:1 copy of the game it wouldn't be ok, and might not fit the theme anyways. But if it's just about the style, grafics and/or music, it would count as assets and would be absolutely fine. Only if you got persmission to use it of course! :)