VR Battle is a helicopter battle game. Shoot approaching helicopters and survive as long as possible. Good graphics but the gameplay is a little, meh..
VR Tank is a tank training game where you shoot targets that are appearing around you. Shoot as many as you can along the track.
Both games are well made graphical wise but the gameplay could be better. So this is not fully recommended by me. The apps can be purchased separately for $0.99 and $1.99 but there is a bundle for both for $1.99 as well.
Unicycle Delivery Service is some kind of Crazy Taxi clone. Make deliveries in a certain amount of time. Nice game but for my taste it is to much motion and rotation in the game. The best way to play would be on a revolving chair. Also the frame rate is sometimes not that high due to many high quality models in sight. You can try before you buy with the lite version of UDS.