This post is to help gamers who are perhaps younger, and don't remember or know some of the great but not well known games through the years.  Also with that would be games that were well advertised, were great games (old or current systems) but bombed in sales.  Any system or P.C.

I'll start:

P.C.   

1. Worms Armegedon (OHHHH, what fun during college years!!!)

2.  Star Control II (a very quirky, zanny, imiginative space adventure; you start out with a single ship (humanoid) and seek to gain other races and their ships in your quest to defeat the bad guys.  One of the races is a suicidal racoon who believes he is the last male or something like that.  You find him a female (out in outer space of course) they get busy and have mass babies; which means you have unlimited crew members instead of paying for them.  You travel through space, explore planets, have active battles with your ships, and if I remember right the quest it timed and must be finished in X number of days. 

Old P.C. game, would be hard to find, but was loads of fun to play.  There is also a competive two player mode that has excellent replay value.  I beat the game with the help of an online guide.  Good luck finding it, greater luck getting to work with Vista ; and more luck than that to beat it without an online guide.

NES

1.  Startropics (there was a sequel as well, but I never played it; zelda type game)

2.  Maniac Mansion (point and click type game, adventure)

Gamecube

Ikaruga (space shoot em up)

Anyone else????

NES: Karnov, Blaster Master, Wizards and Warriors
SNES: Secret of Evermore, Shadowrun

Try mother flippin' Sky Roads.

Seriously, that game was epic. What, with the Joystick and all. Oh, and Executioner...

And, can I hear a Commander Keen?

Good call on Shadowrun. I remember that game, good stuff.

The Genesis had loads of great games that no one talks about anymore. They had a D&D game I loved (can't remember the name), Eternal Champions, Captain America, and a few others. I'm a bit intoxicated now but this thread has reminded me that I need to go look up some of the games I used to play.

If anyone is interested, Star Control II has the odd honour of being the first PC game fully Tool Assited Speedrun. Unfortunately, it wasn't too entertaining. And the AVI may not have seeders anymore.

http://tasvideos.org/1493S.html

worms armagedon was the shiznit, any of you guys remember Commander Keen? also those little Jetpack games were alot of fun... i'm sure you can get these for free now.

Nes: Crystalis
Snes: Strike Gunner S.T.G, Out of This World

Startropics and Maniac Mansion were both great fun when I was little. Didn't Startropics come with a real map?

Some of my favorites from when I was very young:

Shadowrun -- The original, before they made it into a less-than-appealing multiplayer-only shooter. Total agreement with the others who mentioned this.

Privateer -- My uncle had this game on his PC and I used to play it for hours when I would spend the night at his house. I was much too young to understand the economic portions of the game, but I remember thinking it was so absurdly cool that you could become friends with the space pirates and they would then let you fly by without shooting you.

Kid Icarus -- I was maybe five when I owned this, but I remember it being the hardest game I have ever played, to date. Despite the frustration, it was still terribly fun, which is no mean feat. I have no idea why Nintendo doesn't give this series the Metroid treatment and bring it onto a next-gen console. 

Vagrant Story -- Lots of people are Square fans now, but hardly anyone seems to have played this game. I think it was one of their all-time bests.

Pirates!Gold -- On the Genesis. I would rent this game over and over and it never got old. I tried to play the recent Sid Meier remake, but it just didn't seem nearly as fun.

Fallout 1 -- For it's time, probably one of the most innovative RPGs around. If you dig on the style and design of Bioshock, you'll find that this game had a lot of that same 'time-capsule-retro' elements to it. I've never played Fallout 2 (because I am a fool), so I don't know how it compares to the first one.

Final Fight 1/2 -- Sidescrolling brawlers at their (cheesy and somewhat awful) best.

Sorry , narrowed down your post. Kid Icarus was hard but at least I beat the damned thing. :D

I also don't know why Kid Icarus hasn't been brought back to gaming. Then again, I've been screaming for a Bionic Commando game since I was twelve years old (thank you Gameboy for the last great Bionic Commando).

About Fallout, well, if you haven't played the second installation, do so NOW. Great RPG, possibly one of the greatest I have ever played. The freedom allowed in that game paved the way for KOTOR, Elder Scrolls, and almost every other great western RPG that has come out since that time. Brilliant game.

@scotland yard

I don't remember if startropics had a map, but it did have this piece of paper that said "Important don't throw away" I must of been one of the few people who did keep it. It was important, at one point in the game you get a note in a bottle, at which time you were supposed to get that piece of paper and get it wet to reveal the secret code to use the submarine (the code was either 373 or 737, i think?)

@rocket pig

bionic commando!! That was a great gem of yesterday.