It needs something marking where the center of your swarm is. It's easy to have your swarm sort of running into a wall for a few minutes, without realizing what you're doing wrong. Otherwise, good concept! (don't have the patience for it, but loved the game during the time I played it)
Yeah we're gonna add an option for that (that's how we had it at first but made it invisible until we have the option set up). We'll also buff up the tutorial so one is really prepared and understands how the swarming "ai" works.