Game Insight has a nice hit on its hands with Guns of Boom. The first-person shooter mobile game has generated 5 million downloads in the past three weeks, and it has surpassed $1 million in revenues.

That suggests that mobile gamers may be getting more comfortable with both shooters and free-to-play games on mobile. The title comes from Vilnius, Lithuania-based Game Insight. It is available on the iOS App Store and Google Play, and it has lots of five-star reviews on both. It reminds me of Team Fortress 2, only on mobile.

“The critical and commercial successes of Guns of Boom in such a short space of time demonstrates how much demand there is for classic game genres done right on mobile,” said Anatoly Ropotov, Game Insight CEO, in a statement. “With this game, we re-conceived every aspect of the first-person shooter genre, from controls to competition, and players have rewarded these efforts.”

Game Insight said it will regularly update Guns of Boom, and it has released the game’s first new game mode, ‘Capture the Points,’ which brings esports-style clan-based competition to the experience. The update also introduces a new map set in the Wild West, improved weapon upgrades, and a showcase for community-created videos.

Founded in 2009, Game Insight is one of Eastern Europe’s biggest mobile game companies. It has more than 300 million players for its games to date. The company has raised $25 million and it has 300 employees. About 50 worked on Guns of Boom.