Scratch that. Part of it, at any rate.
Level three has one enemy type, with one hit point, and a constant attack aimed at the player, creating a sea of bullets. Player must strike a balance between safety (i.e., blowing them away) and abusing the bonus system to fill up the bar (i.e., putting that bar at greater and greater risk). Not a mental decision but a twitch decision.
Going to sleep on it, and if I still feel good about it, I'm going to get started on those last two bosses.