I had a Vs. Castlevania with graphical glitches all over the place. I swapped the PPU and ROM to a Top Gun board and cleared them right up. While, I put the top gun back on the Castlevania board, and then it had the same issues.

As said before... CHR rom. I've seen replacements online, I've been wanting to experiment on mine. My Dr. Mario also has graphics problems. But, it uses two Eeproms. I know Steph at Hobbyroms has said he could burn me a set for it. May be worth looking in to.

Dual Cocktail system (red tent)

My first was a DK Jr. converted to a unisystem. It had Vs. Super Mario Bros. in it. I would have loved to know about the Vs. systems back when I had it, because I didn't know you could change games out or anything like that.

Currently, I have:
Vs. Castlevania
Vs. Dr. Mario (glitchy)
Vs. Duck Hunt
Vs. Excitebike
Vs. Golf
Vs. Ice Climber
Vs. Super Mario Bros.
Vs. Top Gun (glitchy, swapped daughter cards with Castlevania, because Castlevania is better)

Of all the games I have, I would say Castlevania or Ice Climber. Of course, I have yet to play Balloon Fight, or some of the others that people rave over, so who knows, those could change.

Figured I would drop by and register. Hopefully I can lend some help with the Vs. stuff. I'm still learning as I go, but I've gained a lot of knowledge over the last year, and am always willing to help when I can.