I feel like the asteroids are always spawning in tight little clusters around me. Sometimes it feels like the game field is too small, though I don't know if it's that, or just the pattern they seem to spawn at. It doesn't seem to matter whether I'm hovering near the center or near one of the borders. When they spawn, they all end up right around me and most of them are headed towards me.
When passing wave 3 or 4 is when things start to get interesting as far as being put in a situation that there doesn't seem to be any way out of.