Such an old game now... And it still holds up. After playing other RTS, I still find myself returning to Starcraft. I've played this game to death back when it first launched, and every year I return to it.
A lot of other RTS games always try to over complicate the games. So I like the simplicity, yet still huge variety that Starcraft offers.
The campaign mode is actually good for an RTS. Each three class, now with their own campaign as well. But main characters to follow their storylines. And of course, the many many custom maps and mods, arcade modes, and now the really fun co-op mode!
I wish they'd expand upon the co-op mode and make some 4 player co-op modes. And then redo an entire full campaign with a co-op mode. I'd love to go through the campaign, gaining gas and mats and money, just like the normal campaign. But only with a friend. Upgrading our units differently as we go. And take on a full co-op campaign.