Atari 2600
Laser Gates - Nice game, although it seems a tad bit overrated to me. It usually goes for around 20+ bucks cart-only, scored one for 3 bucks at a garage sale around the corner, has no label but who cares. Gotta play it for a while to see what the fuss is all about.
Atari 5200 (emu)
Carol Shaw's River Raid - River Raid is one of my fav games on 2600 and I didn't think I would see a proper version of it on any other system but the 5200 one is spot on in every aspect. Very nice physics (inertia), graphics have been improved compared to the original and it's quite fast and highly addictive. Excellent version.
Atari 7800
Xenophobe - Gets mixed to bad reviews these days, people compare it to the arcade original and point out the 7800 version flaws, like the infamous jump on up but I have no problem with that, I'm used to pushing up to jump on micro computer games, dunno why some people hate it so much. I really dig the game a lot, simple but effective gameplay, nice graphics for a 7800 game, sound fx are okay, music sucks (that's the ol' TIA chip for ya). Nice difficulty curve, great for an hour or so every now and then.
Donkey Kong jr. - I was obsessed with the game when the cab came out, the NES version was excellent but I didn't have the console back then so I had to cope with the rather inferior C64 and Speccy ports. The 7800 version looks good and plays great, it's (almost) all there and works very well. The NES version might be better looking but I actually prefer the 7800 version over it due to it's overall look-and-feel. Maybe I'm just used to it, dunno, love it all the same.
Master System and C64
Wonderboy - The C64 version was my go-to version back in the day, I was hoping for a proper release on Genny but Sega didn't do me the favour, probably because it had already been released on SMS a few years prior. Compared to the arcade original, the SMS version is almost spot-on when it comes to graphics, sound and basic gameplay, with some exceptions like the skateboard which has a weaker brake effect and thus isn't as useful as the original one, there are also some missing graphics and the level layout is different. The C64 version doesn't look like much at first sight, lack of animation of the main character makes it feel stiff at first but the WB flow is defo there once you really get down to it, that's why I still love this version a lot.
Mega Drive
Metal Dragon - Still can't get enough of this awesome game, IMO it's the best "home-brew" (I prefer to call it pro-brew) game of the last 10 years for the Genny. Mindless but fun shooting action, tongue-in-cheek story, very good graphics, music and sound fx. If you like 2D run and gun shooters, give this one a try.