It's a dated game, but I'll still find the time to gun down more Nazis.
When compared to more modern FPS, Wolf 3D is extremely dated. There's no deathmatch, no co-op, all walls intersected on a perpendicular plane (in other words, every corner was a right angle), no fancy lighting effects, fixed ceiling heights, no stairs or moving elevators (not counting the end-of-stage ones), no full texture mapping, and small enemy/weapon lists.
While this list would scare the living daylights out of the more modern, feature-spoiled gamer, don't let the list scare you. Wolfenstein 3D is still a lot of fun, and despite its severe limitations it stretches this fun over 30 levels (that's more than Doom even!).
The weapons of Wolf 3D are as follows: the knife (useless), the pistol (okay but there are much better ones), the sub-machine gun (pretty good), and the gatling gun (well, the big grin BJ gets when you pick it up speaks for itself). Also there are very few types of enemies, but in groups they can be challenging. They usually don't deviate from being Nazi soldiers. They all have German-sayings when you meet and kill them, and though they get repetitive it was nice technology back in its time.
Wolf 3D is actually a hard game to recommend nowadays, just because it's very dated. With all these limitations, the levels will eventually feel as though they're blending together. If you don't mind this, however, Wolf 3D has lots of content in its single-player which may help make up for the fact that it has no multiplayer.