I find this at least somewhat interesting, both for the metroid reason that CJC posted and also for the possibility of creating a proper SHMUP in ZC (which Zodiac was a nod to, but it was more Asteroids than it was Gradius or Raiden).

Back when 2.11 was all the rage, I did create a short little shmup-esque game in ZC. conveyors pulled you to the right, you had infinite arrows to blast enemies with, but touching anything (obstacle, wall, enemy, bullet) was a one-hit kill. You basically had to get through the whole "level" in one shot.