lol yeah miss those days too. I had always had the opinion the Ack engine was based off of Quake's engine, interesting to realise it was before that and was a fake 3d raycasted one!

It would be an interesting experiment to have a community driven game created in today's environment like unreal as you mentioned and see how it will fare in terms of following, support and 'freshness'. I have a feeling there would be a few already out there but none spring to mind when I think about it.

The original unreal was a great game, it's multiplayer was the beginning to the ut2000 series but the singleplayer was fun and had very memorable puzzles.

Another thing I noticed between older games is interactivity, in Duke 3d and SiN, you could turn on a tap and water would come out, comments would be made if you looked at posters on the wall, I remember running around the game pressing 'use' on all the walls to find secrets and extra health. Interactivity has turned more into physics these days, the worlds feel a little more static because of this, I don't really understand why they can't mix physics and interactivity together.