I've heard them referred to as "survivor-likes" (I believe Magic Survival was the first) or "bullet heaven" (you are the one creating the bullet hell)

the gauge cluster here shows the gear selection on the bottom left, tachometer to the right of that ("10" for 1000 rpm), and the speed in kph on the right. weird no doubt but it looks like there's digital readouts on top for the RPM and speed so you can ignore the curving lines gauge things

the hope that half-life 3 will come out eventually