Space Strafer is a single button game of spaceships, lasers, asteroids and valuable crystals. Intricate scoring mechanisms make it possible to layer risk multipliers and chains to achieve huge bonuses, while a variety of ships cater to different play styles. It's a free game with no IAP's, there is a single ad at the top of the death screen which doesn't force you to wait around, so it's fairly discreet.
The cruiser has slightly heavier acceleration but a faster sideways speed. Here it is heading towards a Megashield powerup (can bash through anything, and retrigger indefinitely). (Mobile - Android)