Heaps of fun, once I got the hang of what I was doing!
At first I didn’t realise the red dots were the (only) shots coming from the enemies—I thought the bright white spots were shotgun blasts or something, and so I kept giving the enemies a much wider berth than I needed to. With that out of the way, I was a lot more ready to mix it up with them and things got a lot more exciting.
I also had to come to realise that “three levels” didn’t mean I’d be given a new room or a new wave of enemies once I took out the first lot… I had to go to them.