Okay so this is a tiiiny bit out of the usual scope of this site here, since it's not technically a handheld game, but... there are certainly handheld versions of the console this game is for, even if it wasn't designed that way originally, so it almost counts. And this is has kind of become my de facto ROM-dumping blog anyway, it's just that until now I've only had Game Boy stuff to post. so here's a thing:
it's Super Tank War, a pretty rare Mega Drive (or Genesis if you're American) game by Gamtec. As with many unlicensed Mega Drive games, it's quite rare - literally the only copy I've ever seen documented anywhere is the one I own, and recorded this video from. It's also pretty much a Battle City clone, which is not an entirely surprising thing for them to have made, considering the popularity of Battle City and its hacks in Taiwan and other Famiclone-heavy markets, not to mention the fact that Gamtec had already made such a clone for the NES, variously known as either "King Tank" or "Super City Tank".
The actual ROM is 256KB, but at that size (in current emulators at least) the music and most of the sound effects don't play; something similar was recently found to be afflicting Link Dragon, and the solution simply appears to be doubling up the ROM to 512KB. Presumably this is some kind of unemulated quirk of the Gamtec mapper, and it's doing something like mirroring 00000-3FFFF at 40000-7FFFF and reading the music from the latter.. for some reason (my knowledge of Mega Drive stuff is pretty much zero, as may be apparent, so I'm not really sure why they would do this, or if that even makes sense in MD terms). But anyway I'm releasing both the 256KB ROM as the proper dump and a 512KB as a hack to get the music working, similar to what I do with raw and fixed dumps of Game Boy games.
Dumped by chôkai from my cart - also special thanks to Raistlin for arranging things.