Over two million users signed up for free-to-play shooter Loadout in its first 14 days of release, logging in over 9 million hours in the game, developer Edge of Reality has announced.

The developer said that Loadout has been so popular that it made getting into the game difficult on day one. Edge of Reality has since improved its infrastructure, but is still having trouble meeting demand.

Loadout’s most notable feature is its weapon-crafting system, with over “44 billion possible variations” for players to assemble, allowing them to define their own class and play style.

“The incredible surge of interest at launch shattered all our expectations, and it unfortunately just became too much for our servers to handle in the beginning,” Edge of Reality CEO Rob Cohen said in a press release. “Very few Steam titles have reached the peak concurrent users we achieved upon release. We’re committed to delivering an excellent game to our community, and we continue to work hard to ensure that our servers provide all our players with the same fluid, responsive, and enjoyable experience across the board.”

Our review found that Loadout stands out against other shooters with its humor, entertaining multiplayer modes, and addictive weapon-crafting system.