Theres a couple of interesting games in MAME that arn't fully emulated which I make a point of check in on every few versions to see how they are going. One of those games is Namco's The Outfoxies, which I found today to be in well playable condition despite a few visible glitches and an unfinished message when loaded.
The game is a bit hard to describe as there isn't really anything else like it, but its sort of a mix between a platform shooter and a fighting game. You choose an assassin from an assortment ranging from a smartly dressed woman to a trained gorilla and you take part in somesort of competition to kill all the other characters in turn in a series of environments ranging from an arms factory to a flying sea plane.
Each environment is basically a free roaming platform shooter level filled with weapons, obstacles and hazards which you have to use against your opponent to deplete a fighting game style energy bar before they do the same to you. What really makes the game unusually good is how everything interacts with eachother. Characters get blown around by explosions, the boat and plane stages rock backwards and fowards, stuff catches fire, sharks attack if you fall into thier tank and so on.
Graphically, the game is about what youd expect from 1994. It makes good use of scalling to zoom in and out of the environment so both you and your opponent are always on screen, as well as rotation for the afformentioned plane and boat. The sound, which has only recently been sorted to a useful degree in MAME, is also what you'd expect.
I've got a few screenies of the game in action since its so difficult to describe and because there is a bit of a shortage of them on the internet, which you can have a look at here - http://photos.yahoo.com/rabidyak1
Note the scaling between the second and third, which are the same stage zoomed all the way out with the characters at either end and zoomed all the way in with them next to each other. Also note the fourth, which is the rotating plane level.
Thats about all I can say about the game aside from go and check it it out, the ROM set is only 8 megs and and its probably one of the most original games you'll play in a while.