Tails VS Dr. Eggman (2P)
From Sonic Retro
The 2P Action in Sonic Adventure 2 for Tails and Eggman is essentially the same as the boss battles in 1P modes, without any upgrades whatsoever besides the Booster/Jet Engine rendering both characters the same abilities. Each defeat counts as one round and the way to win the battle is by the best of two rounds in Shooting mode or just one in Stage Select mode.
The attacks at each characters’ disposal are the same from normal playthrough plus the Rocket Launcher, the Laser Missile (a group of homing Lock-on energy attacks) and Power Laser. These attacks can be triggered every twenty rings collected. In every stage there are some balloons scattered around, containing rings, shields or speed shoes. These respawn shortly after being popped up. Collecting rings gives no proper reward in 2P but adds lives to the 1P counter, but no matter how many lives are lost in 2P these are not added up to the 1P counter.
Beating all of Tails' and Eggman's levels with an A rank will unlock secondary characters for them, Chao and Big respectivelly, both in walkers as well. On the Gamecube remake, Big is replaced by Dark Chao. The two have the exact same attacks as Tails and Eggman, but their close attack is different, Froggy and Omochao respectivelly.
The setting is the same as Mission Street's highway section (complete with the night time). The arena consists in a long stretch of street with two bottomless pits at each edge and four elongated springs that provide some height leverage.
The setting is the same as Sand Ocean (complete with a night time). The arena consists in a rotating platform and three other rectangular platforms. The one to the north contains no rings, but it has a balloon. The ones to the east and west contain rings and ring boxes, along with an upreel that accesses the balloon above the rotating platform. It’s very easy to win by pushing the opponent to the sand.
The setting is the same as the story mode equivalent, but much more cluttered. There are several springs and dash panels that help movement, some walls that provide protection and it’s possible to access the garage’s rooftop to the north.