Chaos Strikes Back.
In most cases I'll tell you that if it takes too long, or if the game is too hard, it's a crap game and not fun... I wouldn't do that with Chaos Strikes Back. In fact, Chaos Strikes Back is the expansion pack to my personal favorite game ever, Dungeon Master by FTL. This was the first, first person perspective (semi) real time role playing game made. It was before Eye of the Beholder, or Lands of Lore, and it was the best by a mile.
Chaos Strikes Back is more like Dungeon Master 2 insomuch that it's a totally different dungeon, and in no way connected to the first, except that you're allowed to import your characters from the first game to the second. And damn dude you better have kicked ass in Dungeon Master if you want to stay alive if your imported characters in Chaos Strikes Back or you'll be dead in the very first room you start out in.
Chaos Strikes Back was released in 1989 (I believe), and I played it for years, almost non-stop working on groups, leveling them up, and trying to figure out the Diabolical Demon Director section. Getting all 4 Corbums was nigh impossible because the dungeon was somewhat randomized and there was no mapping function, so mapping it by hand, which is what me and my brothers had done with Dungeon Master pretty much impossible and the puzzles were really smart.
I was able to get Ku, and Ros, but Dain and Neta were friggin impossible. The Atari ST we had the game on died before any of us could beat it, back in 1996, 7 years we worked on the game, playing Dungeon Master, leveling up our characters till they were practically godlike, then importing into CSB and getting our asses handed to us by 4-packs of Death Knights, the Dragon Den, the Naga Demons, that were more like dragons in that they had the same coloring and blew massive fireballs at you, and the char-black smoking hell hounds.
That game did an amazing job of filling me with dread every time I got near the DDD, and then on top of that Chaos is running around in the middle of the demon director room (he IS the Demon Director after all) tossing god only knows how many different spells that'll mess you up in one shot. Then on top of that, you've got the floating ethereal eyes that'll sneak up on you, surround you and trap you in one spot, and if you were dumb, or were just in a bad fight with demons or those nasty massive poisonous worms and you blew through your mana trying to finish the fight quick, then you're really screwed, because the floating eyes can only be touched by specific spells. Meantime more demons see you, come in to attack and they can blow fireballs through the eyes and hit you.
The whole premise of CSB is really easy. Get the 4 corbums and destroy them in the Ful-Ya pit beyond the DDD, and you can even get your first corbum pretty easily as long as you take it slow and burn through all the dragons in the dragon den and don't allow yourself to get trapped in the room with them, otherwise you're f**ked, but once you thin out the numbers of dragons and can get past them you can get to one side of the pillar where all 4 corbums are... so there you are looking at the corbum you need but the room is filled with pits everywhere, some opening and closing automatically, others are fake pits, others appear close but are trapped doors and if you step on them they'll drop you to the level below and you'll have to start all over, and others you have to close permanently with some key you get elsewhere in the four wings of the dungeon (Ku, Ros, Dain, & Neta).
So you're sitting there looking at that pillar, and you're thinking, man I can do this, I just need to find the other 3 entrances to this room, close the right pits, time my steps grab the corbums and then I can head to the DDD, find the master key, open the room to the ful-ya pit and toss the corbums in the pit and I'm done.
Problem is the monsters are killable, but numerous, and they'll mess you up if you let them get too high in numbers, and if you try and camp out in the DDD with stockpiles of food, water and potions and take it really slow, Chaos is invincible and will mess you up so fast you won't know what happened to you, so that's not possible, you have to be able get all 4 corbums (damned impossible on it's own -not really I finally did it) then be powerful, and fast enough to survive 1 well planned trip into the DDD room open that door with the master key and toss them in. Good f**king luck. I absolutely adore this game, so much fun, but so damned hard too.
Well after my Atari ST died, I'd given up hope on it, Dungeon Master 2 was released for the PC in 1995, and I picked that up and loved it, even if it wasn't quite as good as the first. Then in 2001 when I found a website dedicated to Dungeon Master, Chaos Strikes Back, and Dungeon Master 2.
You can download the game there for free, it's been abandoned, FTL is out of business, and a couple of the original developers are still at this site supporting it through a clone they made. My only problem is that the clone isn't perfect, and it's much much easier now especially in RTC since the monsters barely even attack you compared to the insane attack rate they had on the Atari ST. BUT I downloaded it, played it and after about 6 months of solid work, creating a new group in Dungeon Master, training them, fluxing Chaos and beating the first game, importing, raising them up even higher, and finally figuring out all puzzles, which are simply ingenious, and very tricky at times, and blasting through the DDD without anywhere near the same challenge as before, I finally got all 4 corbums, which was the real achievement to me, and then made it to the ful-ya pit and destroyed them and beat the game, all for a 16-bit cut scene saying congratulations.
I still pull this game out annually to play through it again. Now that I know what to do and how to do it, I can plow through it in about 40 hours of gameplay. But I started playing at the age of 10, played until I was 17, picked it back up when I was 22 and I was 24 before I beat it. Nothing will ever compare to that game, not for me at least. Hardest game ever, most amazing game ever, best gaming memories ever.
If you guys want you can get it and try it here:
http://dmweb.free.fr/