It's a decent fighter even though I'm a little biased but here goes.....

User Rating: 8 | Mortal Kombat: Shinken Kourin Densetsu GB
This was the first videogame I ever played. I was eight years old, and I found my uncle's old Game Boy. This was the only game that was in the case, so I popped it in, and played for hours. This game is your basic MK game. you have a cast of characters to choose from including Sub-zero, Scorpion, and Raiden. Simple button combos determine attacks whether it be a quick punch, crouch kick, flying kick, or finisher, the moves are easy enough to figure out.
The graphics look like the original MK only even more pixelated, and the arenas aren't too large.
The sound is also subpar. it has a decent background theme, but it is very crackly and hard to here. If you are looking for a fun oldskool MK game for under $5 I would recomend getting this one(although with systems like the PSP and DS, this does show its age)