I don't remember how I came across it, but there is now a version of the old CGA game sopwith made with my favourite platform-independent graphics library SDL. It's at http://sdl-sopwith.sourceforge.net/. The coolest of all? Networking now can be done across regular TCP/IP instead of the proprietary network protocol the original used. I tried it (starting two players on my computer and connecting to myself) and it's cool!
On a similar note, another old game I really liked, Andrew Braybrook's Paradroid, now is cloned - and updated - in SDL. It has higher resolution and better robo-artwork than the original, and also you can use the mouse to shoot diagonally (your opponents could do that in the original, but not you), otherwise it's excactly the same. Ah, I remember the first time I managed to control No 999 :-) . And how tough the second and third storage bays used to be. Full of sentinel droids :-)
Link: http://freedroid.sourceforge.net/