The Classic Doom 3 modification is a remake of the original 1993 Doom game, by id Software, in Doom 3. The main emphesis is that of brining the older game up to date in a modern graphics engine. The project makes use of all of Doom 3's advanced graphical features while retaining the atmosphere of the original game. This mod only works with the original retail release of Doom 3, patched to version 1.3.1. This mod does not currently work with the Doom 3 BFG Edition. Some BFG source ports are available that reportedly work with this mod, but are untested. The project is complete, and only includes the shareware levels.
This is definitely worth the download. In fact, even if you don't like Doom 3, you should buy it just for this. I couldn't get past the first map in Doom 3, but I beat all 9 levels with almost 100% completion in one sitting of this. This mod is an almost perfect example of how to make a good game on a new engine.
The demons are much easier to kill than in Doom 3, which puts the player back in power. In this mod, it doesn't take five shots with the shotgun to take down an imp or zombie. One major flaw of this game is that the armed zombie enemies (shotgun guys and pistol zombies) are much too accurate and quick to react. Also, the imps and demons' intro animations are too long, I usually have them dead before they are done showing off!
There are other problems, the player is too slow, there is no automap, there are no rad suits, Lite amp goggles (lite amp goggles and rad suits are needed much more in this game than in the original), or blur spheres, it's hard to walk across even small patches of ooze without getting hurt, the spectres are too hard to see, the textures are repetitive at times (I got lost because the textures looked the same in certain areas), some parts of the levels are too dark, and the models are gray and blob-like, but these problems are inherited from Doom 3, and I assume that it was too much work to fix them. I only mention these things as observations and suggestions for future modders.
EDIT - I noticed that somebody else said that the chainsaw is useless, I agree, mostly because it seems very hard to aim and control, because it lacks a feature the original chainsaw had: the original chainsaw jerked you toward your enemy, so it was hard to lose your grip on him.
After playing this game, I am much more likely to make a Doom 3 mod of my own, since I now know that this engine is capable of much more than the included levels. Thank you for making this.