As of October 5th, 2021, Killing Floor 2 is now pay-to-win, since one of the more important classes for higher difficulties (the Berserker/designated tank) has received a few nerfs back in the summer of 2021 only to gain a paid weapon that helps fix most of the problems that the summer balance changes have introduced. Tripwire/Saber Interactive has no plans on giving a base game alternative to the Berserker's DLC Piranha Pistol, and their community moderators will shut down suggestions regarding this.

2023-07-21 EDIT: It is possible to play around Killing Floor 2's pay-to-win since you can usually get a weapon bundle off the trading forum for the price of a Team Fortress 2 Mann-Co Crate Key. You're still gonna be spending money on a Berserker buff, though all of your money will go to the Valve Corporation rather than Tripwire seeing any amount of it. I'll still mark this review as negative since it's better to not get the game at all. This is more of a useful piece of trivia if you've made the mistake of buying this game early on in its lifespan.

I still find the game to be a fun wave-based shooter, though I'm gonna have to give this game a thumbs down due to some personal concerns I have regarding pay-to-win and when I voiced my concerns about Tripwire/Saber Interactive's business practices with recent balance patches, I was told to "stay on-topic" when discussing about certain in-game strategies, mentioning how an in-app purchase more or less fixes some problems that were introduced in the summer balance patch.

Oh, and to further add to the negative review, this game has been bloated to hell and back to such a point where the recommended requirements for this game are no longer adequate. I'm running this game on a system that can trade blows with the Xbox Series X and I'm actually using a custom low INI tweak in order to have decent performance. If you have a gaming PC from the early to mid 2010s, this game will likely be unplayable

2022-05-27 Edit: Criticizing P2W business models can get you banned from KF2's Steam community hub, as I was threatened by a moderator to drop my mentions of an in-app purchase when discussing game balance, even though IAPs are a factor to consider when talking about balancing in other games where in-game items cost real world money.