Dubbed the R8 Revolver, the new pistol replaces the Desert Eagle, and players are complaining that it is grossly unbalanced.
Valve's official description says the weapon "delivers a highly accurate and powerful round at the expense of a lengthy trigger-pull," but a secondary attack allows players to fan the hammer, boosting fire speed.
The CS:GO subreddit is flooded with complaints (and jokes) that the R8 is too powerful and needs to be nerfed or banned.
Professional player Adam Friberg told players via Twitter to "don't judge to [sic] quickly," saying he expects Valve to patch out the issues shortly.
Meanwhile, the eSports League will be using the previous version of the game at this week's CS:GO season 2 finals, based on player feedback.
"With the number of game play changes and weapon changes, we all felt that this is really important to maintain the competitive spirit of the event given the amount of money and prestige on the line," said ESL's VP of pro gaming James Lampton.
"Having the patch land very close to the event (and players already being onsite), we don't think it would be reasonable to expect players to have enough preparation, so we are rolling back."
Given the popularity of the game in casual and pro spheres, the pressure's on Valve to fix the issue rapidly.