ICO:
http://www.gamespy.com/games/2763.shtml
REZ:
http://www.gamespy.com/games/3451.shtml 

ico is underrated? I thought it was generally considered l33t. I dont have much of an own opinion about it because Ive only seen it a little. 

Undying
Why? Great story that unfolded as you played. Lots of little details to pick up on. Fun gameplay. Very nice environments.

Unfortunately, though, the demo really hindered its success. If the demo was better I would have bought it when it first came out instead of waiting until it had been out for a while. And with most Unreal-engine games, the texture resolution was varied throughout, which created inconsistency and was disappointing. Boss combat was usually pretty poor.

Blair Witch Volume I: Rustin Parr
Why? This is one of the VERY few games that I ACTUALLY FELT LIKE I WAS PLAYING A MOVIE. Visuals were dark and brooding. It was very much like an adventure game, but at the same time there were distinctive shooter elements, and it was combined perfectly. There were were sidepaths in the story that ended the game prematurally, but not before showing you a cutscene that gave more details about the story. There were several truly spooky moments. Action was kind of cool.

On the downside, there was a bit too much backtracking in the woods, and some of the puzzles are a bit weird. 

b0rked bold tag! 

The biggest problem with them was that you needed 3dfx cards to make them run good without having to add a couple of hundred MHz to your cpu. 

I knew that would be a some what controvertial pick. It's not like the game isn't well thought of, but I still think it's underrated. The sp had genuine innovations and the mp was just plain fun. It's a bright spot in a long list of shitty licensed games. Had it been possible to map for it I would say that it's far better than any of the Quakes. The bond universe could have made for many more interesting maps. 

I would argue that it is painfully underrated.
It got wonderful reviews and much praise, but Sony didnt promote it at fucking all. And it also suffers very hard in the shelf-space fight.

"The fuck? A game about holding hands... Oh, look, shiny objects with boobies!"

*wanders off towards the DOA Volley-game stand* 

Nolf/Nolf2 (great mix of action/realism, intelligent mission orientated design that allows quite a lot of immersion and interaction, and it`s funny!)

kingpin (arguably the greatest looking q2 engine game with probably the first solid locational damage based gameplay. Cool settings and enemy cries of FUCKER!)

soldier of fortune 1 (kingpin`s contender for best looking q2 engine game, lots of varied diverse locations, probably the best visual use of locational damage, and tons of fast in your face action)

Keep in mind that I`m only referring to the sp parts of these games. 

most of mentioned games are underrated compared t o CS, diablo2 and uhmm Sims ? 

Cyber Empires - I must have beaten the game like 20 times. It was cool.

Stunt Island - In the campaign you had to complete stunts to be the best stunt pilot, but the really cool part was that you could set up your own stunts, perform them, film them and edit them into a movie. It was really cool. I spent countless 16 hour days and nights on that game. Has anyone ever played it? Ive never heard of anyone else who ever did. 

A friend of mine was similarly hooked on Stunt Island. 

Doom
GTA 3
Command & Conquer 

(Well if you can have GoldenEye on a list...) 

Tetris Attack
Super Mario World 2: Yoshi's Island
The Simpsons: Bart's Nightmare

I lurve SNES games :D 

definitely battlezone 2, bought it after shambs advice and it really is cool.

operation flashpoint. best military sim ever with the most freedom ever. period.

freespace : the great war. awesone space combat and wickedly designed ships. 

command & conquer
descent II
california games (NES)
skate or die (NES) 

also puzzle fighter for ps2 

Command and Conquer and Descent II are underrated? 

as doom is. 

YES! California Games rocked! 

was that the random mash the joypad game I remember playing? :) 

Scampie, Yoshis island is a real cracker... one of the best games ever! Thats the most perfect platform game Ive ever played, at any rate.

Played through the entire game on an emulator, even though I just had to use the sucky keys... it has so much character I just couldnt stop playing it. Regrettably I never owned it on my SNES (and I sold the console when I was younger and more foolish... a decision I certainly regret now).

Youve just reminded me I have to pick up a new Gameboy so I can play the new Yoshis island on there - it apparently has some new and different stuff to the original as well. 

but imo it would have been better off without the parts were you transform yoshi into different vehicles... 

Especially the people who gave their reasons which were pretty interesting.

Aard, I have definitely heard of Gothic1/2 - I almost always checked out the screenshots (mostly too dark for G1) and a few articles too. Unfortunately the 6.7gig demo size for G1 put me off trying it a bit :P. But I agree they seem pretty underrated compared to, say, Morrowind. 

I think we all forgot about one classic game of all times - Minesweeper by Microsoft. The game that is always interesting and fun. Even Linux has it's version of Minesweeper. This game cannot be old cuz it has no age.

I like it and can play it everyday :)