NES

Metal Storm

Title screen

Level 1

Anti-gravity trick (running along the ceiling)

Power-up that lets you attack while inverting gravity

Level 1 boss

Level 2 has red & white blocks that flip around depending on your gravity orientation

The boss intro screen

Level 2 bosses

Level 3

Level 3 boss

Level 4, where you stand in a moving box

Level 4 bosses

Level 5, another moving box like level 4

level 5 bosses

Level 6

Level 6 boss

Level 7

Level 7 bosses

Final "boss"