I'm sure the finished product is still a ways away, but how if you had to guess when it would be done, what would you say?
Think it'll take longer than OiaLT did, or less time since you have more experience making games now?
Just enjoy the ride. OiaLT is finished, and has been for a while, and still holds up fantastically against all the games that are still in development. Think of it like older games in other genres where the AI is not a massive fail. People will be playing OiaLT 20 years after finish, like X-Com or CivII, right up until we get full VR immersion ... which is part of the current game. Don't sweat the graphics of the time, roll with the story.
The graphic tools used in Eternum, and embedded music, and the occasional scrolling camera, take more time, regardless of "experience."