The re-release will include all the expansion packs as well as the base game. The original title didn't include co-op play, but it was instead patched in as a user modification. Mercenaries, Black Knight and Vengeance all support co-op play.
You're also going to want to check out the excellent MekPack 3.1, which was just released for the MechWarrior 4 engine. This content, created by MekTek, introduces widescreen and high-definition support as well as upgraded and new Mech models and textures.
. I dont think I played it for more than 30 minutes. I didnt know what they hell was going on. Haha so i'm keen to give it another go 
