Kenyuu Densetsu Yaiba [剣勇伝説 YAIBA] Game Sample - Game Gear (Japanese) 

Original Air Date: September 15th, 2008
Kenyuu Densetsu Yaiba is a pretty cool maze-themed, search-and-explore action game for the Sega Game Gear that features good audio/visuals, a thin plot, and simple gameplay. In Japan, this game was based on an animated T.V. series named "Yaiba Adventures" and features differences to relate more to said animated show.
Playing as "Yaiba" in the year 1994, you are one of the universe's last hopes of stopping an evil cyborg tyrant named Yaiba, who is using his lesser cyborgs and cyborg chiefs to further interstellar mischief. You are aided by a female named Adina who works back at some headquarters; she gives you basic (but usually useful) advice as you need it, but not much else.
The game is quite easy and has the strange habit of making items on floors you've previously visited (like health, Psycho Sword for special abilities, Bombs, etc.) reappear upon revisiting them, so you generally know where you can go when you need a pick-me-up. Even if you die, you can continue mostly from where you left off with replenished health and P.P. You have to go through seven different areas and can only leave by defeating cyborg chiefs, which you can find using your radar (it beeps when you are close). The one main qualm I have is that while this is a single player game, you need two controllers to play efficiently (the second can be used to go through menus). This was due to most commands being used already and due to the limit of three buttons.
This video goes through the first three areas and shows several things in the game. I purposely shoot Yaiba with the "Psycho Sword" (because Adina doesn't explain it) to show you that she will actually reflect it back and take a large portion of your life. Enjoy.