Hrm, so let's see - this thread gone into disuse sadly, so here's one more to add to the list:
Freespace 2 Source Code Project:
When this came out, it was among the best space sim shooter games at the time for graphics, gameplay, and plot. Although several years old by now, Volition, Inc. actually released the source code for the game out to the public, and the project listed above has been updating and modding it ever since.
Basically what this means is - (1) it's free for you to play (noncommercially), (2) there are massive campaigns and mods out there that rival the original campaign in plot and length, (3) contrary to what you might expect from a several-year old game, the graphics and gameplay has continuously been updated and (4) because of the dearth of good space sims out these past years, Freespace 2 SCP is arguably
still one of the best pure space shooter sims out there.
The Freespace 2 SCP actually has an installer that'll install everything you need to play (original game, all the extra finished campaigns, the mods, etc.).
The best part though is - whereas the original game was PC only, you can play this game on OSX just fine - the SCP even has a OSX installer package included.
Click to expand...