Eye of the Beholder

I have fond memories of this game, because it was the first computer AD&D game that was different from the traditional Gold Box series released by SSI. While the Gold Box series had turn-based combat, with a third-party view of the battle, this is the first game of the Black Box series, with combat taking place in the same 3D dungeon screen, and no distinctive turns. Basically, you swing your sword when you click on it, and cast spells when you manage to open up your spellbook and select a spell. Of course, there are shortcut keys that allow you to do some of these faster, but your reaction is still crucial to winning encounters.

The story is simple enough, there is trouble brewing under the sewers of Waterdeep, and you and your party have been formed to go check out what is the cause. And as the name suggests, the nemesis is actually a beholder, which is a big floating ball of flesh, with a central eye capable of negating magic, and ten eyestalks that are capable of casting a different spell each.

Eye of the Beholder departs from the traditional Gold Box series in that there is actually some form of puzzle solving involved in the game. Gold Box series games attempt to incorporate puzzle solving into them, but most of them are feeble attempts and the games still hinge heavily on hack-and-slash. But Eye of the Beholder (aka EOB) actually managed to put in some puzzles that challenge people to think.

The hint book actually provides maps and events for each level, and also hints for the special quest found on each level. The teleportals found on each level can also provide a challenge (they can be confusing) or a quick method of getting from place to place.

So while this game may not be that great now, compared to 3D games like Neverwinter's Night and Oblivion, it did break new ground back in the old days by allowing real-time combat in the 3D dungeon screen. And that, in those days, was a big break from the norm.

Wikipedia's entry
A fan site with walkthroughs and maps
Another fan site with all three games in the series
Eye of the Beholder module for Neverwinter's Night