Critters
They are everywhere, not only annoying but lately also dangerous if you enter their districts. Easy to kill but hard to not miss.
Dogs
Schäferhunde, Doggen, Rottweiler - the Nazis have a certain fondness when it comes to dangerous quadruped. They are fast and deadly.
Infantry
The German Wehrmacht is carefully arranged for any kind of terrain and situation. Even though their troops are weak, their sheer amount is what makes them dangerous.
Mutants
German scientists have spent years of research to find ways to cybernetically or bionically enhance their slaves. They are stronger, but not unconditionally smarter.
Docs & Cooks
Medical doctors or kitchen butchers - from a certain point of view, they seem to be the same. Their syringes and cleavers are a heavy treat to your armor.
Ubersoldiers
Every corps of the German infantery has their heroes, stronger and deadlier than all the single soldiers and guards. Make sure to kill these first.
Occult
Supernatural powers are not only legends, they obviously exist and the Nazis try to fully take advantage of these. Believe what you see before it kills you.
Bosses
Hitler has appointed a handful of henchmen to his personal commitee of consultants, each of them more crazy and ruthless than the other. And each of them with special deadly abilities.
Tanks
If you run into one of these with your Walther, intelligence suggests to run. No need to be intelligent to agree. Make sure to have Panzerschreck with you, or even better: Your own tank.