The subtitle "EO" is unique to the Gamecube version of this game and stands for "Easy Operation." Due to the Gamecube controller's somewhat unorthodox design, a special control option was added to this version of the game called "GC-ism," which allows players to execute special and super moves instantly by just tilting the C-stick. Players who want a more traditional control scheme can instead select "AC-ism" (or Arcade-ism) before the start of a match.

Capcom vs. SNK 2 is a 2D fighting game that pits characters from two rival fighting game franchises against each other. Players can create teams of up to three fighters and compete head-to-head or go solo to tackle Arcade and Survival Mode.
The game features characters from various fighting game franchises, including Street Fighter (Capcom), Darkstalkers (Capcom), King of Fighters (SNK), Samurai Showdown (SNK), and others.
Capcom vs. SNK 2 also features an expanded version of the "Groove" system seen in the previous game that changes how your characters play. Where in the previous game there were only two grooves, now there are six--each one based on a fighting system from a Capcom or SNK fighting game.
With all of that included, it's no wonder the announcer of the game says: "This is the first dream event of the 21st Century!"