Capcom have confirmed the Resident Evil: Revelations has online Co-Op for 2 players on their Japanese website for the game. The site also confirms Local Wireless options and StreetPass functionality, and that the game will arrive on a 4GB cart.
The Co-Op mode is called "Raid Mode" and appears to be a fresher take on the Mercenaries mini-games. You play as either Jill Valentine or Chris Redfield as you eliminate enemies in scenarios taken from the main campaign .Raid Mode is playable in both single-player and two-player variations, the latter of which allows you to team up with a fellow survivor either locally or over the internet.
As you'd expect, you earn points for killing exploits that are calculated at the end of each level to give you a rank. you'll also collect loot and parts to upgrade your weapons.
Tsukasa Takenaka speaking to EuroGamer:
"The story mode in the game is something we created with the single-player experience in mind. I would like everyone to play the game in their bedroom with the lights off and headphones on. That's the way to experience the mode. At the same time, these games we create, we know they're really enjoyable when you're able to share some of that experience with a friend. Multiplayer is very important and that communication is something that resonates with everyone. We felt putting Raid Mode in, in this kind of structure, allowed us to do that for this game as well."
This looks like it's shaping up to be a very cool game...