Good times indeed.
The game is easy. Very easy. Its abit of a timesink tho, since you can and most likely will find yourself wondering where to go, and especially where you have been, already. This is due to the lack of a map you can peak at.
The only thing that will keep you orientated, is your intuition and how well your memory deals with geometrical sizes. This is something i personally value.
The monsters are easy, theyre essentially just a bunch of humanoid nazis with a small variety of armament at their disposal. Pistols to submachine guns to poisoned daggers. Thankfully, you yourself can wield a much bigger, and much more effective weapon (eventually), so you will find taking out the trash to be slim pickins´.
The levels are basically maze-esque one-level floors or mezzanins if you will. The only noticable difference between level one and level one-hundred is the colour of the walls and the quantity of adversaries, so be ready for a visually monotone experience.
What makes this game so fun, tho -- is the fact that because of the constrained character controls, you will feel "barred in", like several restrictions have been laid on your character. This works well with the fact that it is a prison you are trying to escape from. Also, the game feels patriotic, and shooting nazis is generally good, clean, wholesome family entertainment as far as im concerned.
So get out there and listen to some SS soldiers yelping:"ach, mein liebe"!