Gargoyle's Quest (Game Boy, 1991)

Capcom was one of the most prolific game developers from the mid-80's to late-90's.  On the NES, they created Mega Man, Bionic Commando, and had a relationship with Disney that produced some of the best licensed titles of all time.  So in 1990, when the Game Boy came along, they mostly did what all other third parties did:  they made watered-down ports of their console games.  There was one huge exception though, and that was Gargoyle's Quest (1991), a completely original Game Boy game that took big risks, made grand innovations, and is still just as good today because of that.
You play as Firebrand, a gargoyle called back to the ghoul realm when an army of "destroyers" attack, attempting to take it over.  Legend tells of the Red Blaze, a mutant gargoyle, who defeated the destroyers several millennia ago.  Firebrand must become the Red Blaze and save his people from the wicked invaders. Unlike most video game plots of the era, this one has twists and turns that yield some real surprises.  At one point in the game you run into a town where the villagers (who are zombies and demons) call you a fraud and tell you that another gargoyle is the true Red Blaze because he has the eternal candle.  Of course you defeat him in battle and prove yourself.
The game does well to keep you engaged in the story which seems massive when compared to other Game Boy games, and it does this through the clever mixing of genres.  There is an overworld map where you go to different towns and get into random enemy encounters.  Action segments of the game are done in a 2D platforming style, well suited to a handheld game.  In these action stages, you can jump, fly (for a limited time), cling to walls, and breathe fire.  I've never been a fan of the "double-jump" in gaming, because it almost never makes physical sense.  In a game like Super Smash Bros, it just seems like the characters are bouncing off of thin air.  In this game however, it makes perfect sense because the main character has wings.
This is also complimented by level design and upgrades.  Each level has a different concentration and variation on different aspects of the gameplay which keeps things interesting.  Some levels may have a focus on combat while others have very few enemies, being more like obstacle courses.  The levels are all well designed, but being on the tiny Game Boy screen things can feel a bit cramped sometimes.  There is a system of upgrades to go with the other RPG elements of the game, which will grant you more health, higher jumps and longer flying times.  The last level is a masterfully crafted combination of everything you have learned.
This is a great game, but also a flawed one.  As I mentioned before, there are random encounters on the map screen (which are looked down upon in traditional RPGs) which play like miniature platforming stages.  These break up the pacing a little and are the cause of a few undeserved deaths.  The difficulty curve is also a little weird.  Like Kid Icarus, some of the harder stages come early on when you are weaker, and then when you've gained more health things get a little easier.  The final confrontation with King Breager is also kind of anti-climatic.  He cheaply blocks most of your attacks by holding his arms up and fires homing sparks at you, and after exhausting several lives trying to strategise, I finally found a sweet spot by his head where I spammed attacks at him and won.  It was disappointing, to say the least.
Don't get me wrong though, this game is definitely worth playing.  In twenty years, it has aged surprisingly well, and its great points overshadow its bad ones.  It offers a great challenge without being terribly frustrating.  It experiments with gameplay styles in a way that makes it a wholly unique experience.  Capcom is known for making games that push the graphical capabilities of their platforms to the limit, and this is no exception.  This is one of the best looking and most atmospheric Game Boy games.  On the NES, there would come a Gargoyle's Quest II, and a third game on the SNES called Demon's Crest.  The critic Derek Alexander said that this is Capcom's "most consistently good series to date," and I can't disagree.