Well, if you are not near my age you probably don't even know what a Turbo Grafx 16 is but anyway, it has a few pretty great games but kind of struggled to keep up with the likes of Nintendo and Sega, which at the time anyway were dominating the marketplace. That is another story.
This game was just incredible to me and anyone else that grew up appreciating games that kind of fell in line with Gauntlet. The great thing about this game was that it actually looked really good (better than the home ports of Gauntlet at the time) and if you had a the write amount of controllers and a splitter, you could actually play the game with up to 5 players.
You were able to play the game as a fighter, thief, warlock, witch, bishop, elf, bard, or gnome. Later on in the game other classes are unlocked but to be honest with you, there is very little difference between the various classes.
The best thing about this game wasn't just that you could play endlessly with your pals, it also had the added benefit of many of the dungeons being randomly generated, so no one could become the expert at it all.
This game spawned many sequels and also can be easily emulated online if you so choose. It obviously doesn't stand up to today's graphical standards but at the time of its release (1989), it was a pretty exceptional and welcome addition to my game library.