I googled it, thought that the game was very beautiful for an oldie, but then saw on wikipedia it was published in 2001.
I’m too old to think of a 2001 game as “old” 
For the record, mine is probably Master of Magic from 1995.
I don’t think it has so much to do with age. I’m 30, and I certainly don’t think of 2001 games as old. And seeing Civilisation 4 mentioned in these threads amazes me. I only played that game for the first time a few months ago.
Tetris. I still play Tetris. I’ve given up on “Pong” though.
Umm – Solitaire?
I still fire up NetHack once a year or so. First published in 1987, last updated in 2003.
I found Heroes of Might and Magic II for Droid so I have that on my tablet. It doesn’t have the quests but there are a lot of maps available.
Not counting Tetris, probably the original Dungeon Master on PC
You have been eaten by a grue.
Still chipping away at my Baldur’s Gate game here and there. It’s on the remastered version, so it’s got some modern amenities like widescreen support and a scalable UI, but the core game is the same one from 1998 so 16 years old.
I go through Doom and Doom II once every couple of years. I’ve still got my original CDs and DosBox makes it work, but I usually just download the port for whatever console I’m using at the time.
I don’t usually play any game until they’re pretty old. To me, 3D engines still seem like the “new thing.”
For example, the two games I have running right now are Baldur’s Gate and Fallout Tactics. I only have a few hours a week to play them though.
As for the oldest: about once a year, I pull up my Genesis emulator and play the ROM for Master of Monsters (1991). Battle for Wesnoth is essentially the same game updated, but there are some things about Wesnoth that I’m not quite as fond of.
(For those who want the details: Master of Monsters makes you the most powerful character on the board, even from the very start of the game, but binds you to your home squares. Wesnoth starts “you” as a weak and mobile character no different from any other. The Master in MoM is ridiculously powerful; even with the most powerful units, it requires several of them to take him down. Your character in BfW is never more powerful than his peers. BfW also removes the long-range magic powers that further emphasized the power and uniqueness of your main character. So BfW loses that bad-ass-wizard wish-fulfillment that I so love about MoM.)
Hah, I loved that game and its half-assed translations. My friend and I used to play it and ham it up. “Prepare to feel the wrath of… CARTHAGO!” “I’ll stop him with my Marmaid!” 
The Microprose Magic the Gathering game that came out in 1997.
I downloaded the Android port of Karateka a while back. You can play it in green or amber monochrome if you want to really recapture the Apple II feel. That damned eagle is still as annoying as ever.
Warlords (fantasy turn passed strategy game) was first released in 1989. Theres now a “warlords classic” iPad app which is very faithful to the original and still plays really well.
Played many games in the last few weeks.
Thieves and Kings, not sure how old it is.
I still play “The Bard’s Tale” from 1985. The original one that taught me how to map dungeons.
I, too, still play Emperor: RotMK. I still also play MoO II from time to time.
I had that on Commodore 64. Don’t forget to come out of your fighting stance when you get to the princess…
How do the controls work on the droid? I get easily frustrated by virtual joysticks on touchscreens because they just don’t work for me.
I would pay good money (maybe $3 or so) for someone to put Buck Rogers Countdown to Doomsday on my Droid tablet.
I still play Star Control 2 occasionally, which I first played during its initial release in 1992.
I like it so much I wrote up a comprehensive walkthrough that touches every aspect of the game, even the ones that aren’t required. That walkthrough still lives on here.