The smirkers are moody creatures. Your objective: Keep them happy!
In each level you will get a number of smirkers with different moods. Clear the level by converting all the smirkers to green so that they can continue living happily. You play the game by firing green smirkers at the other smirkers to change their mood. Colliding with a green smirker will improve the mood whereas colliding with a black smirker will worsen it.
A level is cleared when all the smirkers are green and happy. On the other hand, be cautious: if no green smirker remain, you fail the level and need to start it again.