The Law of Hobson-Jobson maintains that words borrowed from another language will be conformed to the sound set of the borrowing language. I would add two corollaries:
- Even if the original has no sounds foreign to English, if the original spelling suggests an English pronunciation, then English will likely win the day
- unless elite speakers approximating the original pronunciation manage to convince others to pronounce it their way.
Most Americans pronounce the German car Volkswagen as VOKES-wagon, although the German FOLKS-vahgen contains no sounds not present in English. The spelling wins out. The television show Grimm overflows with mangled German that's been thoroughly "englished."
Elite speakers will pronounce the names of composers as closely to the original as they can, so the composer Wagner (VAHG-ner) is pronounced differently then someone named Wagner they happen to know. There are, however, limits. The ř in Dvořák is a rare and difficult sound, so most approximate it with a zh-sound. French nasalized vowels also are readily jettisoned.
This means that the gaming community can basically pronounce names as they see fit. Wolfenstein looks German, so you can pronounce it as VOLF'n-shtine if you like, or like a VW, go for pronouncing it as if it were an English name. Polish orthography is rather daunting, but as a last resort, ask someone from Chicago. The Windy City has a high concentration of Polish-Americans. Plus you can get into an argument about pizza.