If you know your World War II history, Kalypso Media wants to give you a way to show off your knowledge and a way to save money on its new strategy game.

The publisher is about to launch Sudden Strike 4, a WWII real-time strategy game, for the PC this spring, and it’s rolling out a mobile companion quiz app to promote that game today. Sudden Strike Quiz is available to download for iOS and Android, and it will test your knowledge of the history of Second World War. During Sudden Strike Quiz matches, players face off against friends and strangers on topics related to the conflicts of that calamitous confrontation. If you are able to identify more weapons, locations, and important dates than your opponent during these head-to-head trivial battles, then you’ll get the win.

But with this app, you’re not just playing for bragging rights. Each win will earn you a medal. If you get enough medals, you can get up to 25 percent off of Sudden Strike 4’s price. The game is selling for $50, but it’s 15 percent off on Steam right now at $42.50. And Kalypso has confirmed that you can stack the two discounts together.

This is a new kind of promotional event for the launch of a game. Kalypso told GamesBeat that it’s not aware of any other companies trying something like this.

“As far as we know, this is the first time there has been a companion app that is a quiz for an RTS,” Kalypso marketing boss Mark Allen explained in a note to GamesBeat. “It’s certainly rare for sure.”

Sudden Strike 4 is the latest strategy game from Kalypso, which is likely best known for its Tropico banana republic political simulators — although, more recently, its Viking: Wolves of Midgard action role-playing game has attracted a lot of attention on Steam.