The Great Halls should appear after Prisons Level 3, and the Aqueducts is accessible on Floor 3 of the Prisons in the secret room. Sometimes the enterance does not appear in version 0.3 as the result of a glitch, but you can still move to the middle of the room and enter there. The Aqueducts has different enemies of a higher difficulty.
It's possible that the Great Halls aren't appearing when they should, I'll have to look at that for the next update.
The game is not done yet, the only point in continuing to run the game (especially if Great Halls are not appearing) would be to try to find different gear, but ultimately there is no end to the game yet, as it's still in it's Alpha phase.
Lol if it's running past Floor 3 then yes, the levels are going to start getting longer and longer, as 3 is supposed to be the cap, and the floor length is based on what floor you are on. I did remove the Dark Elf for now, since her animations are not done yet, but don't worry she will be back in the near future.
Don't forget that this game is in it's Alpha state, and is still mostly a demo of the final game to come. Check back for future updates, there's a lot more planned with this game, but as a solo dev content can take a little while to churn out. Thanks for the bug reports.