Blizzard revealed the names of the map and what they'll entail:
Left 2 Die
Left 2 Die is a co-op mode based on the StarCraft II: Wings of Liberty, zombie-infested campaign mission Outbreak. The design team has modified the mission so that players can share tech trees, earn research points by destroying infested buildings during the day, and create elaborate ground defences.
This will be a round-based mini-game where you'll play as a zealot warrior chef who is skilled in cooking. Each round will feature a specific meal and players will have to fight for ingredients across the map to collect them and make the meal. The player with the most points at the end of the room will be named Executor Chef.
Similar to Bejeweled, you'll be able to gain new units based on energy you get from matching 3 of the same jewels. If you line up the correct coloured jewels, you'll get to send strong units at your opponent. If not, you'll be stuck with marines and be really up against it.
This is a 5 vs.5 mini-game inspired by the Warcraft III mod Defense of the Ancients and will feature 12 "hero" characters such as Muradin from Warcraft.
All four maps will be free, but Blizzard is still working on them so there's no release date as yet.