1v1's- The 20 something rounds, you take on polygon forms of the characters on a normal difficulty. When you beat every character, they get harder for the next time they come back. So at about 60 or 70, they're on expert. You only get 3 lives.
1v2- 2 characters are against you at mainly all times. Everytime you kill one of the people, you get a 5 second countdown from the announcer, for when a new enemy enters. Difficulties get harder and harder by kills you make instead of how many times they die.
Hoard- 3 against you, each enemy gets 2 lives, so you have to get them 2 times. Difficulty gets higher by kills you make.
All the Polygon Mode types are played on Polygon Boss Battle field. Items are active and hazards can be toggled on and off.