Yep, I've played it. A friend of mine also swears by it. I was leaving for an overseas trip that was expected to take two months (but ended up being two weeks) and he insisted that I beat a nice and challenging old school NES game before I go. It was fun.
About Guardian Legend itself: 8 way directional movement (takes a lot more frames of animation, so I give props to the devs), nice Zelda-ish exploration, plenty of powerups to find that increase gun power and HP, lots of secret weapons, nice graphics, typical catchy NES music with the always amusing underlying 8-bit bass, and the shooter stages that precede the boss fights are really fun. They throw a shitload of lifeups at you as you fly, which is nice for me because I've always sucked at shooters, especially the one hit and you're dead ones. Only one-hit shooters I can play are run 'n gunners like Contra and Metal Slug (pwnage).
Also, the main character of Guardian Legend is a hot chick in a red space bikini. You get to see her anime-ish portrait at the end. For what that's worth, there's some incentive.
