GIF: Starcraft Remastered Most people already own a copy of the original StarCraft. But if you don't, or you're looking for some oldschool RTS action, the original game is available right now.
Update: Brood War version 1.18 has been released on the Battle.net forums for all regions now, not just the PTR server, and you can download it here. Note that you'll want to run the game with administrator privileges the first time around.
StarCraft will be officially free once patch 1.18 drops, a move made by Blizzard ahead of the release of StarCraft Remastered in the winter. The patch is expected either today or early tomorrow, but for now the developer has made a build available for the game's public test server, which you can download from the Battle.net forums.
You'll need to make a PTR account if you want to play StarCraft 1.18 online, but the campaign can be enjoyed without any such hassles. The whole download is just over 1.5GB, according to the file on my HDD, and it comes with support for UPnP, compatibility for Windows 7, 8.1 and 10, an observer mode, customisable keybindings (oh my God yes), and support for windowed or borderless fullscreen/windowed fullscreen mode.
If you're interested in the full list of patch changes, the Battle.net post has them all. The main heads up is that if you do want to play multiplayer, you'll be doing so on a server in California (as that's where the PTR server is based). The full public release will have support for servers much closer to home, but if you just want to relive the Terran, Zerg and Protoss campaigns, this works just fine.
Just unzip the Starcraft folder to somewhere of your choice and run Starcraft.exe to enjoy. (And for those playing on Mac, don't worry: another update is coming out in a few days with support for OSX.)