Thank you for the great feedback! I failed to add a more descriptive introduction apart from the game page, but the gist of it is; you need to maintain as large a swarm as you can, as your score is multiplied by how many there are in your swarm. It's ok if half your swarm dies, there are constantly spawning yellow "flatsvermers" that you can recruit by flying next to them, and having a larger swarm increases the chance of picking up powerups and new recruits.
In short, Flatsvermers strength are in their (dwindling) numbers :)