Four Play - Stargate / Defender II - 8-bit Computer Comparison 

My thoughts: 4 good versions this week, but I think the Atari 8-bit version just about edges it as has a lot more sprites on screen without too much slowdown, controls really well and the sound effects are spot-on. After that I'd probably say Commodore 64, it's a bit harder (as you can probably see) and doesn't have as much polish as the Atari version. Next is Apple II, which is a remarkably good port all things considered but the floaty controls do let it down a little bit. The PC version is very similar to the Apple II actually, except a little bit worse in every regard. So my final ranking is Atari 8-bit > Commodore 64 > Apple II > PC Booter

The NES / Famicom version is underrated. Yeah, I said it.