He was involved with the game ports of various id properties through the 2000s, starting with Quake III Arena.

After he got hired full-time, Duffy managed to secure Timothee a contract to work on the new cross-platform GtkRadiant editor project in 2000.

[15][16] This was followed by him releasing the source code for GtkRadiant under the GNU General Public License on February 17, 2006.

[26] A year later John Carmack revealed that ZeniMax Media "doesn't have any policy of 'unofficial binaries'", and so prevented id Software from pursuing any sort of third-party builds as it had in the past, be it Linux ports or experimental releases, and he then suggested the use of Wine instead.

[27] On July 2, 2012, he was announced to have joined Frozen Sand, which was then developing Urban Terror HD.