The Unreal campaign can still be an entertaining romp today, if you like breaking out of prisons and shooting up tons of aliens. But if you're after a little more intimacy with your alien jailbreak, why not play the whole thing in VR?
Unreal VR is an open-source project at ModDB that is basically porting the 1998 re-release of Unreal into the latest Unreal Engine, adding VR support along the way.
The project isn't complete yet, but you can download a demo of the opening level. It'll work just fine if you don't have VR, but the real joy is being able to immerse yourself in the UMS Vortex Rikers (the prison ship where Unreal begins). There's no enemies, but the opening level does look sharp, which makes me wonder how nice a re-release of Unreal in UE4 would be.
To start the game in VR, simply extract the contents of the .RAR file (available above) to a folder of your choice. Run the StartVR batch file and you'll be good to go; if you don't have a VR setup, the batch file will load up the project anyway.