Only GOOD Freeware Games.
As it turns out, now that PC gaming has been well established for now over a decade, free PC games are in large supply. The issue at hand truly is finding games that are COMPATIBLE with your computer. A focus of this particular website is to point you in the right direction toward games compatible with the current line of PCs, such as for the Windows Vista/7 crowd. Now, I understand that a lot of people are still running XP. This is actually ADVANTAGEOUS. Lots of great older games have 16-bit components such as installers, making them straight up incompatible with newer 64-bit PCs with Vista or Windows 7. Some people can try to get around this with Microsoft Virtual PC, but 3D Acceleration doesn't work for this. I know work is being done to get around this, but I'll admit I am not currently aware of a good solution. This is not to say there isn't one out there. So alas, I still can't run Rogue Squadron on my compy I bought in 2009. However, thanks to DOS emulators like DOSBOX, old DOS games can be run on just about any computer! The following games I mention are either newer freeware games that have been verified to be able to be run under 64-bit Windows 7 Home Edition, or classic DOS games which require DOSBOX.
AND NOW FOR WHY YOU'RE HERE IN THE FIRST PLACE:
Good Freeware Games Compatible with 64-bit Windows 7
Under construction! The Marathon Trilogy definitely won't be the only game listed here...
The Marathon Trilogy
This was recommended to me by a friend. Like Halo? Well, this is a trilogy of first-person shooters created by Bungie Studios, the makers of the Halo series, in the 90s. The trilogy was most popular for Mac users (only Marathon 2 was released for Windows). The games in the trilogy were released as freeware in 2004. The open source Aleph One game engine (an open source version of the Marathon 2 game engine) lets you play the games on Mac OS X, Windows and Linux!
Learn about the Marathon Trilogy on Wikipedia.
Get all of the files you could possibly want. There are some custom levels on here.
Go here to get all three games, which run under the Aleph One game engine (the original Marathon was converted by fans to run under this.)