While there hasn't been an official confirmation on the existence of replays in Demigod yet, it is very likely that there are replays and as I haven't seen a replay thread so far it's time to make one.
Before beginning to list up the features which Demigod replay system should have, I have to admit that I have very ambivalent feelings towards replays. I do enjoy watching replays of interesting matches, be it in Starcraft or Supreme Commander, however there are a few thinks which aren't so cool about replays.
The first, is that strategies spread a lot faster with replays then they did in the old times (for example in starcraft before they added replays), so the most exciting time period of any multiplayer game, the one where everyone is experimenting around and many divergent gamestyles exist, is alot shorter than it would be without replays.
Another thing I have seen very much and dislike is that newer players very often imitate the gamestyle of good players without even knowing what they are doing - some may say that the learn faster that way and it might even be true in some cases, but I think that it would be more fun for them and their opponents if they experiment on their own, rather than imitating a proven tactic and either failing badly because they didn't know what to do when something unexpected happened or winning because of imitating the strategy good enough and having been lucky that the enemy reacted as expected.
Please don't see that as a generalisation many new players take replays as a good inspiration and do explore the game themselves but especially in Warcraft 3, I noticed how many players, not even necessarily new players, imitated the style of the progamers and lost badly. On the one hand because they just didn't know what to do when I didn't play "standard" and on the other hand that they just can't execute a strategy of someone who is alot better and faster than them. Without replays more people would realize that a strategy which is very good at top level isn't necessarily a good strategy on their level.
Okay enough of this, nobody can deny the entertainment value of replays when you watch them solely or mainly for fun. So here are some things I'd like to see in:
Live Replays like we had in GPGnet, I do hope that Impulse is capable of that.
The ability to watch replays together (as in Starcraft, strangely enough Blizzard skipped that one in Warcraft III).
Recording Chat in replay , its fun on the one side and also reduces possible flaming as people know its being recorded. (it should be possible to turn that off though, especially for teamchat)
We all know why replays just can play forward and you can't just select any time, but having some "keyframes" every 5 or 10 minutes would be really cool. It surely should be possible to save all conditions of a single tick either in the replay itself (which surely would increase their size) or at least when watching the replay, so you can jump back 5 minutes rather then watching it from beginning on if you want to see a certain scene again.
A small replay manager where I can search through my replays using filters and sort stuff, should also display map, gamelength, players (including which demigod) and the winners. GPGnets replay vault had most of this stuff but I would like to have it locally for my own replay archive as well.
A way to quickly change the Demigod Version to an older one so we can watch old replays, even cooler would be if that happens automatically when trying to watch an older replay.
I doubt everything of that comes true but I hope at least some of it happens in one or another way.