Just found some PC downloads of the full games for both Metro 2033 and Duke Nukem 3D. Metro will be free until the 16th, and Duke Nukem is only available for 48 hours.
Metro 2033: HTTP://WWW.FREEMETROGAME.COM/
(All you need to do is like the page)
Duke Nukem 3D Atomic Edition: http://j.mp/DukeNukem3DFREE
(Free from GOG.com)
Metro 2033: HTTP://WWW.FREEMETROGAME.COM/
(All you need to do is like the page)
Duke Nukem 3D Atomic Edition: http://j.mp/DukeNukem3DFREE
(Free from GOG.com)