No, unlike DARGHUL, Teudogar really ends when it ends. You can't keep playing after finishing the game.
However, it remains up to you if/when to actually trigger the game end (via Actions Menu, action End, or in some cases, by talking to some of the main characters):
You needn't do this, since the game has no time limit. So you could play the game almost all the way to the end, and when you get to one of these fateful dialogs (e.g., 'Let's do battle with the Romans', or 'Let's form the alliance', etc), you simple answer 'no, not yet', and keep playing.
The reason things are this way is that there are several dozen different game endings in Teudogar, and some of these would lead to radical changes in the game's world. (E.g. too early battle against the Romans would lead to extermination of your tribe, burning down of all of your villages etc.) So, letting you continue playing in such a changed scenario almost would have required writing a new game, creating a new game world, new dialogs for everyone, and so on. And this for each and every one of several dozen possible game endings ... simply couldn't do this.
(In DARGHUL, I could, because in that game's fantasy setting your actions will not have such a fundamental impact on the game's world, i.e., things more or less remain the same even after you've finished the game, so it's comparatively easy to let you continue playing - a few changes to the game world, a few hundred additional dialog passages, but no more. With Teudogar, it'd have been 20 to 50 times the amount of work to do that.)