Now it's time to write some stuff about this revolutionary game made by id Software.
Wolfenstein 3D was born in a mess of side-scrolling platform games, like Crystal Caves, Dangerous Dave, Secret Agent etc, bringing up features never seen before in those days. It's true that the game doesn't have many things to do, since your main objective is to reach an elevator to proceed to the next level. The registered version of the game comes with six episodes, each one with 9 levels to beat, where the 9th one is the boss level. There is also a secret level in each episode, but there isn't a logical reason to search for it in the regular maps, since you'll lose a lot of your time just to visit a place which, in its essence, has nothing new.
You have a score system in Wolfenstein 3D which corresponds to a value that increases when a treasure if picked up or for when an enemy is killed. Also it increases when you beat the actual level faster than the "par time" (a suggested time from the developers) or find some secrets passages. The only logical reason to accumulate score is to gain new lives, which are your limit deaths before you see "game over". But don't worry about it, considering you have a fair save-and-load system in the game. So, if you get hurt or die, just restore the progress.
Finding secrets in Wolfenstein can be fun, but not really necessary. To find secrets passages, you have to close-in a wall, and press the corresponding key to open doors. If there is a secret passage in the touched wall, then it will be pushed until you can reach a new room, with treasures, ammo, weapons, health packs or secret levels. Personally, I only search for secret entrances if I'm running out of ammo or health.
Now to the most fun part of the game: killing your enemies! It's very cool when you find a guy and shoot it, because at this time you'll draw attention of nearly all nearby enemies, and they will start to search for you. You'll hear the b*****es shouting after been alarmed, doors opening and closing and eventually the sounds of their weapons firing. I highly recommend playing in the last difficulty setting, called "I'm the Death Incarnate", because a higher the difficulty means more and stronger enemies around, making the game much more interesting and challenging.
There're four weapons in Wolfenstein 3D: The knife, the pistol, the machine gun and the chain gun. All weapons, except the knife, use the same type of ammo. You'll only use the knife if you're running out of ammo. Personally, I found the pistol and the machine gun obsolete after acquiring the chain gun. However some players like to use the early weapons at some occasions, like when killing dogs and less powerful enemies.
About enemies, there are just a few. Basically, there're dogs, zombies and soldiers with pistols or machine guns. The bosses are particularly different, because they may come equipped with rocket launchers and chain guns. The tough fellas are also very resistant and it takes time to kill them. In the 2nd episode you will find the zombies: mutated soldiers that have a pistol in the chest; they fire faster than normal and have a little more health points than the regular enemies. In the 3rd episode, at the last level, you will find some mage ghosts flying around that cast fireballs against you, although these ethereal enemies can be attacked normally.
The levels in Wolfenstein 3D are labyrinth-like, save a few rare exceptions. This can be either a good or bad thing; it really depends of your taste. The 9th level, as I said before, is where the boss resides. It's a short level with a lot of ammo and health packs, sometimes defended by a lot of goons until you meet the final boss of the chapter.
As you can see, it's a fun First-Person Shooter and even today it is worth playing. Just be sure that you don't really mind playing a game with ancient graphics like the ones in Wolfenstein 3D.