This game is one darn good fighting game.
The game has solid 2D graphics with partially 3D backgrounds. The animations are very fluid, except with some minor framerate issues. Some of the super special attacks are visually stunning.
The sound in this compilation of KOF games is spectacular. Each character is given a certain voice that is given by voice acting. Although there are no cutscenes, the grunts, openings, and victory dances show that the characters have a personality.
The two versions are only slightly different. KOF 2002 has many characters that are absent from the 2003 version. The two versions have different end fights and one version has a arcade mode feature that allows you to choose between two characters to fight.
Both versions of the games have a large selection of characters. Both also have a survival mode that challenges you to defeat as many CPU controlled as you can without being defeated yourself.
As an alternative to the Capcom classic Street Fighter, this is the game you should look for.