Some games can go out of the typical theme and still be good games. I usually accept Zelda II as a good sequel, although a bit reluctantly. Specially at the beginning of the Nintendo era, the games had to experiment with different techniques and game styles. There were also changes in ambience, look, and even enemies.
A great example for this is Super Mario Land on the Game Boy. Just look at it: the only semi-recognizable enemies you will find are the goomba, the piranha plant and the turtle, and even then the latter explodes instead of leaving the bouncing shell behind. Even the boss is not the typical DK or the now classic Bowser; instead we have the alien creature called Tatanga.
Just look at the cast. Although the princess you have to rescue is still Daisy, the enemies are flies, spiders, tarantulas, easter island faces and sphinxes. Also, the areas are not part of the Musroom Kingdom. We have an area that reminds us of Egypt, another one of China (with immortal mandarins jumping around, out to get you!) and the Easter Island.
What makes this game so great if it is so out-of-place of the typical Mario universe? I think it is the notion that Nintendo had of bringing a game so weird is just fantastic. We see, literally, how our favourite plumber fights visitors from another world in places reminiscent of our own Earth. It is just so weird to see our hero in a different place. The enemies and areas that appeared on this Game Boy classic never appeared again. Which, in my opinion, is really a shame. I would love to see a little bit of Tatanga action again (although there is a reference on Mario Land 2, if I am not wrong).
Also noteworthy in this game is the great music. My favourite song is the one in world two. Extremely catchy. Just listen to this great 8-bit rendition:
If you get your hands on this game, a playthrough is definitely worth it. Specially enjoy the water and the air levels, where Mario takes a vessel and shoots at its enemies. And for those who don’t have enough, they can replay the whole game in a more difficult version after finishing the game. Too bad you can not access it until you finish the game first.
May they smile upon your way!