Works extremely well, until I try crouch-jumping (space-ctrl-W). Firefox interprets this as ctrl-w and asks me if I want to close the tab (and the mouse pointer doesn't get re-confined again).

I'm not even using a QWERTY layout, so I have to contort to press W... It's a common issue with US-made games.

There is also "uplink", which is Half-Life: Uplink, the demo of the game. Those are several levels that were originally part of the retail game but were cut and then used as a demo.