Quarth makes a shooting game's controls serve a spatial puzzle. You move a ship across the bottom of the screen and fire blocks upward into the irregular formations descending above it. Completing a solid rectangle makes that formation disappear, creating breathing room before the next problem arrives.
The important decision is often which shape deserves attention first, since firing carelessly can make a simple gap more complicated. Larger completions can be useful, but survival depends on recognizing a manageable solution before the screen crowds your ship. Its spare presentation leaves plenty of room for the satisfying moment when an untidy mass becomes one clean shape.
