ButterFlight is a strategy game where you must "collect" a certain amount of butterflies.
The game presents you a 10 by 10 (or 9 by 9, depending on the game mode) big playfield, randomly filled with different types of butterflies. Your job is now to arrange at least three butterflies in a row, by simple exchanging the position of two adjacent butterflies. Once three or more are in a row, they fly away and new ones fills the gap. But you can only change position of butterflies, which will then form a row; if this is not the case, you can't move them.
Depending on the game mode you play (4 different available), you have to make horizontal and vertical rows, or vertical and diagonal rows. And the number of butterflies you are rotating (two, three, or four) also depends from the game mode.
Each level has an unique type of butterflies and a certain amount which must be collected. Those are blocking the others, so you must plan which butterflies you use for a row. Once all butterflies from this unique type are on the playfield, all butterflies flying away, and you can proceed with the next level.