Dawn of the Tiberium Age (DTA) is a stand-alone mod that combines Tiberian Dawn (C&C 95) and Red Alert. While classic mode gets as close to the original game-play and balance as possible, Enhanced mode provides improved game balance and a lot of fun new stuff. DTA features many customization options for Skirmish and multiplayer (where you can play as GDI, Nod, Allies and Soviet on over 200 maps), challenging original singleplayer missions, as well as co-op missions. Since this is a stand-alone mod, you don't require anything but the mod itself to be able to play: the original game is not required.
A new co-op mission made by me (Rampastring), to be released with the next update for DTA 1.13.
Quick bit I have to ask due to reasons: What are the odds of the current co-op missions getting singleplayer versions?
Low. We (or at least I) will most likely keep SP and Co-op missions separate from each other, since due to the nature of multiplayer, SP missions and Co-op missions are somewhat different. The only exception right now is Reunification, but even with that mission the SP and Co-op versions are very different.
Also, Co-op missions have higher priority right now since we already have a good amount of SP missions but few Co-op missions. In addition, we've found out that many of our players like co-op multiplayer, so I think there is large demand for more co-op missions.
Another thing to add is that some of the Co-Op missions can be perfectly played in Skirmish by adding AI players. Be aware that your AI ally will just try to play as if it's a regular skirmish map (in other words, it'll immediately try to deploy and build a base if possible), so it can't always be counted on (so you'll likely have to pick an easier difficulty than you would when playing the Co-Op map with a human ally).
Yeah, I already figured that bit out. Ant mission was a bitch getting started, though. That's why I asked.
Oh, well, thanks for the info anyhow.