From the Store description:
Enjoy 5 exciting games modes full of non-stop, action-packed 3D shooter fun!
Vehicle Defense - Race through the streets as you man a turret, blasting every vehicle that is in pursuit. Fend off attacks by enemies who are using everything in their arsenal to take you down, from assault rifles to rocket launchers.
Assault - Take to the streets as you run and gun down enemies in huge sprawling 3D environments. But don’t think it will be easy, the enemies are fast, cunning and trigger happy. Plus, they have a tank! Luckily, you have an assortment of weapons at your disposal.
Sniper Defense - It has been said that all legendary snipers can hold their position against waves of ruthless enemies. The golden rule in Sniper Defense Mode: If it moves, shoot it!
Battle Royale - The ultimate survival mode where your only objective is to live. In this mode, you have no place to run and no place to hide. Your only option is to face the waves of enemies head on. Do what it takes to get to the next wave.
Mission Mode - When you’re in the battlefield, all that matters is the objective. A good soldier always completes the mission, and nothing can beat the hound pounding fun and action of Mission Mode. Each objective is exciting, and you will get to blast so baddies while you are at it too.
As far as I can see there aren't any in app purchases - it seems to be monetised through you watching video ads (typically for Candy Crush) in order to earn the in-game currency. These take 30 seconds each but are same-y enough that I wish there was a way to progress a bit faster through a small IAP. It's all about balance. (If I've missed how to buy currency then please comment below!)
Here's Cube Wars Battle Survival UWP in action on my Alcatel IDOL 4 Pro:
You can grab Cube Wars Battle Survival UWP in the Store here. Have the developers pitched this just right or is it in fact too hard for beginners? (Or I might just be rubbish at this sort of title!)