The area in which The Witness, Jonathan Blow's Braid follow-up, ends is perhaps the most interesting thing he has ever made, he reckons.
He recently entered "personal crunch mode" to rebuild The Witness' endgame into "something more epic".
"This was one of the most productive periods of my working life (maybe the most productive) and I think this area, all taken together, may be the most interesting thing I have ever designed," he said in an update on The Witness blog.
"However, it may be a little too difficult for the player, at the moment! Today I playtested this endgame and one other area of the game, with a game designer friend of mine, and it took nine-and-a-half hours to play through these two areas (six hours for the endgame, 3.5 hours for the other area).
"I think this is a little long, so I am going to be tuning these areas and cleaning them up a little bit."
The Witness, a first-person puzzle game set on an openworld island, currently has 440 puzzles, with more on the way. The screenshot, below, shows the island in its current form.
Blow had intended for the game to offer between ten and 15 hours of gameplay, but it now looks like it'll be much longer.
Blow said: "Sometime in a month or two, I'll do some playtests with people who have never seen the game before, and we'll see how long it really is."