Hexen II for DOS (Announce)
It can be a good example for CPU intensive DOS game.
Hammer of Thyrion - it is a open source port of Hexen II which also supports DOS!
http://uhexen2.sourceforge.net/
The original datafiles are requiered but you can find it pretty easily as Hexen II is now considered as abandonware.
Try f.e. http://www.invalid.invalid/
EDIT by rr: removed abandonware URL
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DOS-u-akbar!
Complete thread:
- Hexen II for DOS - Laaca, 26.04.2008, 21:35 (Announce)
- Hexen II for DOS - Rugxulo, 27.04.2008, 01:04
- Hexen II for DOS - marcov, 27.04.2008, 15:45