Android seems to have become infested with games that have a large amount of things in common: they all pay homage to an extremely-successful Xbox game, and have won the hearts of players the world around.
Spirit plays a lot like Hyperlight, a game I've previously reviewed. The graphics are extremely similar in that they pay homage to Geometry Wars, and both take place on a flat, 2D plane. Spirit, however, has different mechanics that set it apart: instead of relying on twitchy tilt controls, your faster-than-light spacecraft is steered by your finger.
Lacking an on-screen joystick, I can only describe Spirit's controls as "relative." They don't require any specific positioning - instead, drawing a circle anywhere will make your ship fly in that pattern, even if it's nowhere near where your ship actually is.