German Shepherd Dog
This doggy is specially trained by SS instructors. Well, they are really fast,
but if in a long distance they are not a thread. They run to you, and then bite you. However, they biting doesn't do many damage if they aren't in big groups - otherwise they can be dangerous.
STRATEGY: You can easily kill them with knife. However, use pistol when you encounter them in big groups.
DAMAGE TAKING: 1 shot and 1 knife stab.
SAYS: Woof (sees you), Off (dies)
YOU GET: 50 points
 

German Trooper
They are rather slow and weak. Equipped with pistol. They can be troublesome when encountered in bigger patrolling groups. Your standard enemies, you will encounter them nearly everywhere. Just watch your back, then everything will be OK.
STRATEGY: Use pistol. In bigger groups machinegun will be ok.
DAMAGE TAKING: 1 shot when close or hit in back, 2 at distance. If you aim bad he can take 3 shots. 2/3 knife stabs.
SAYS: Halt! (sees you), various screams (dies)
YOU GET: 100 points, used clip

Schutzstaffel Guard (SS)
Considered as the most dangerous guards in Wolfenstein and SoD. This guy carries a big machinegun and is very powerful. Also, they are wearing a bullet-proof vests, so killing them won't be easy. In groups, they are DEADLY!
STRATEGY: Careful at close range. Use machinegun.
DAMAGE TAKING: 8/9 shots, 11/12 knife hits.
SAYS: Schutzstaffel (sees you), Mein Leben (dies)
YOU GET: 500 points, machinegun or used clip

Mutant Guard
Mix the SS with officer, and here it comes: the ultimate killing-machine. These things were created by Dr. Schabbs. They are extremely strong and fast. Their pistol is almost rapid-fire, so it's not easy to bring them down without any health problems.
STRATEGY: Shoot with machinegun, and don't let them shot at you!
DAMAGE TAKING: 8 shots, 10 knife hits.
SAYS: Nothing (sees you), Argkkh (dies)
YOU GET: 700 points, used clip

Officer
Probably Nazi officers. They are stronger and more powerful than normal guard. Also, they are nearly as fast as the dog. They are equipped with strong pistols, and without any regrets they will just shoot you down. Don't let them get at small distance. They can be a real danger when in bigger groups or with SS guards.
STRATEGY: Use only machinegun!
DAMAGE TAKING: 5 shots / 7 knife hits
SAYS: Spion! (sees you), Nein, so vas (dies)
YOU GET: 400 points, used clip

Big Guys
On the end of every episode, you will encounter a bigger, tougher and stronger guard, also
known as Big Boss. Here is the list of "tougher boys":
 

Hans Grosse
The leading guard of Castle Wolfenstein. This guy has two really big chainguns and he knows how to use them. His sister is Gretel Grosse. Unfortunately, when somebody's strong, he usually doesn't have mind. And that's Hans.
STRATEGY: Chaingun and strafing when he shoots!
DAMAGE TAKING: About 60 shots
SAYS: Guten Tag (sees you), Mutti! (dies)
YOU GET: 5000 points, golden key

Doctor Schabbs
The mad scientist that created powerful mutants. His weapon are syringes filled with mutant-changing acid! So beware of them unless you want to be a mutant! Also, don't forget that he can't do a "rapid-throwing"!
STRATEGY: Medium distance. Strafe and shoot!
DAMAGE TAKING: About 50 shots
SAYS: Wahahaha! (sees you), Mein Gott in Himmel (dies)
YOU GET: 5000 points, finished episode 2

Hitler Ghost
These guys float on Hitler's floor on Episode 3 and throw deadly fireballs to you. If you are so lucky to kill them all, prepare for battle with real Fuehrer! The fireballs are rather slow, but they take much more damage than normal shots!
STRATEGY: Get back, choose chaingun, and strafe!
DAMAGE TAKING: 30 shots
SAYS: Toter Hund (sees you), Ahahaha! (dies)
YOU GET: 2000 points

Hitler
Two true Hitler forms. Beware of the Mech version - he's actually very tough and four Chaingun will make you... sick. After blowing out his  Armor, you will face Hitler without a shell. He has only two Chainguns, but he's faster than any other bosses.

STRATEGY: Get near the steel blocks and strafe. When you will destroy his armor, you can easily kill him by choosing chaingun and strafing when he shoots.
DAMAGE TAKING: 70 shots - armor, 40 shots - Hitler himself
SAYS: Die, Allied Schweinehund (sees you), ScheiBe (armor out), Eva, Auf Wiedersehen (dies).
YOU GET: Double 5000 points = 10000 points, and finished episode 3
 

Otto "The Poisonmaker" Giftmacher
Another mad scientist, this general is responsible for nearly coming chemical attack on Great Britain. So it's important to kill him! But that's not an easy task - he's got a rocket launcher and he can blow you out of the game in a second. Unfortunately, the rockets aren't very fast, so you can easily strafe his attacks.
STRATEGY: Just a lot of strafing.
DAMAGE TAKING: 50 shots
SAYS: Eine Kleine Amerikaner! (sees you), Donnerwetter (dies)
YOU GET: 5000 points, finished episode 4

Gretel Grosse
Head guard of fortress Erlangen. She takes care of chemical war plans. Like Hans, she's pretty stupid, but she carries two Chainguns which will change you to a piece of dust. The strategy - the same as Hans.
STRATEGY: Chaingun and strafing when he shoots!
DAMAGE TAKING: About 55 shots
SAYS: Kein Durchgang (sees you), Mein Busen (dies)
YOU GET: 5000 points, Golden key

General "Fat Face" Fettgesicht
Leader of Giftkrieg operation, he hides in Offenbach military complex. It's your last ultimate fight. He has a big rocket launcher and even bigger Chaingun! He's very powerful and has so many guards that he can easily kill you.
STRATEGY: SHOOOT!!!
DAMAGE TAKING: 70 shots
SAYS: Erlauben sie, Bitte! (sees you), Roseknospe (dies)
YOU GET: 5000 points, finished game!

Pac-Man Ghosts
Probably the most stupid enemies you encounter in game! These floaters are Pac-Man classic game enemies, and their lair is in Episode 3 level 10. You want to be a pacman again? Eh! Get treasury and RUN! RUN!! RUN!!!
STRATEGY: Just run!
DAMAGE TAKING: They can't be killed!
SAYS: Nothing!
YOU GET: The Pride knowing you Ran from Pac-Man!