Oh yeah, I played Uru before it went online with the old CD rom. I actually preferred it to the online platform version. RealMyst really improved that first games performance. I enjoyed it for the nostalgic aspects. Did you ever play the fifth and final game, End of Ages? That one was a huge let down. You could really tell they were having money problems at that point.
I played the Uru single player also. I tried out the online one but seemed more if you like to socialize than play the game. I heard the difference is in the online one you have to have other players help to do actions together to solve some of the puzzles. In single player you could solve them all yourself. I'm not sure if that was true or not, the few times I checked out the online game everyone was just standing around in the main city center and barely talking. But I guess it's like a chat room of sorts if you do it that way.
And no, I haven't played the 5th game yet. While searching last night, I found most of the Myst games I bought, but am missing 3 and 4, yet I found 5. There was one online sight that I bought games from and it changed into something else. They screwed everyone over who bought games previously and that library now has disappeared. Anyway, I think they were in there.
