GravCat ($0.99) by Monster Robot Studios makes for a charming arcade game where your kitty goes for joyrides in space to collect power cells, all while hopefully keeping himself alive.
You can either be riding along something like an asteroid or floating around on nothing. Gravity always acts towards your wheels, so when on an object, you’ll be riding in the direction your cat is facing. However, when sitting on nothing, your cat always just moves towards his wheels (regardless of which direction they’re pointing).
Having three directions you could be accelerating in is a bit confusing at first, but you’ll get the hang of it soon enough. Since, when in free flight, you’ll be moving only towards your wheels, the only way to change direction is to rotate the ship using the bottom right and left arrows. The top left and right arrows change your left and right facing orientation and will give you a speed boost when double tapped.
There are other movement controls in place, but you’ll be shown those in the first few levels which act as a tutorial.
The objective is to collect all 10 power cells scattered around each map which has various obstacles to navigate mainly in the form of asteroids and planets which are completely harmless to you. There are dangers though.
Some planets have a small sun orbiting them which will kill you instantly. There are also space bugs crawling around that can only be killed with your wheels. Touch them with any other part of your ship and you’re done for. Be careful as you only get four lives.
Rotating and zipping around empty space is a simple yet fun challenge that is sure to keep you entertained for at least a while. Give it a try.