Most purpose built gasoline 2-strokes dont have crankshaft induction. This is where running in reverse would cause problems. Airraptor is right - the piston moves in the same direction. Regardless of the induction path, they should operate in either direction providing the timing is adjusted accordingly. If using Glow ignition, nothing needs to be done other than to start the engine the other direction.

I dont see the point in reversing the cylinder/piston though.. Unless induction or exhaust routing were difficult, it shouldnt need to be changed the way I see it.

For those that think running a 2-stroke engine in reverse changes the compression ratio or how 'well' the engine runs, point me (or anyone else) to some literature that explains this phenomena. I'm intrigued as to how this works differently on a gas engine than it does on a glow engine.