Blaster Master

You've fallen down a hidden manhole into a world of creatures so terrifying they'd scare the rats away. You can panic and perish, or blast your way through an endless maze of tunnels, searching for the secret passages to your escape. And that's the easy part. Because the Masters of the Caverns lay waiting - prehistoric creatures so powerful, so gigantic, they literally fill your screen! So load your arsenal and get ready for BlasterMaster.

In Japan the game was known as "Metafight". When being brought over to the west, not only was the name changed, but so was the plot, some of the sprites to compensate for the changed story, and an intro was added.