This mod is intended to enhance Wolfenstein single-player and improve gameplay balance, making it feel more like a true sequel to the 2001 game Return to Castle Wolfenstein. Retrostein combines the powerful weapons, paranormal abilities and regenerating health of Wolfenstein 2009 with the tough enemies of RtCW, ensuring that the game maintains a fair level of challenge throughout. Now Heavy Troopers and Elite Guards will be enemies to be feared, and you will want to buy ammo for special weapons like the Panzershreck and Tesla Gun. Retrostein also includes some (but not all) of the HUD/movement features from Neurological's "NeuroWolf" mod, designed to make the game feel less "consolized".
The Pump Overdrive is perhaps the most desirable Flammenwerfer upgrade as it increases its range. In the unmodified game it was not available until the Black Market vendor at the end of the Airfield mission, which was disappointing as you could only use it for a few minutes at the end of the game. Retrostein allows you to buy it after completing the Castle mission, allowing you to actually get some use out of it. The usefulness of this upgrade is reflected in the price being increased from $500 to $750.
The Improved Fuel Pump allows you to fire the weapon continuously for a longer duration, which is fun but only occasionally useful. It was therefore strange that it was more expensive than the range-increasing Pump Overdrive upgrade, so the price of the Improved Fuel Pump has been lowered from $1000 to $750. Therefore the total cost of buying all the Flammenwerfer upgrades remains unchanged.