I have never seen an FC Twin before, the idea is the right one. Unfortunately, unless you like second-rate sound, occasional graphical glitches and don't play the games that don't work on it, best get real Nintendo systems. Finally, the button placement on the included gamepads is off in NES games. If you are using a SNES pad in a NES game, the optimal button translation is as follows:
SNES Y = NES B
SNES B = NES A
While SNES B = NES B and SNES A = NES A may be easier to grasp, your thumb will appreciate the above translation better.
As far as games that don't work on it, there are at 11 known NES games. These include fan favorites like Castlevania III and Gauntlet, good games like Rad Racer II, After Burner and Laser Invasion, and six Koei strategy games. SNES games that may not work include Super Mario
RPG, Kirby's Super Star and Kirby's Dream Land 3.
The FC Twin is cheaply made and not worth whatever they are charging.
