At a quick glance: four months for the engine (which they wrote from scratch [1]) and, based on the budget [2], roughly nine months for crowdsourcing and pre-production (setting the overall story and puzzles, deciding on the look of the game, building small proofs-of-concept), seven months for production, three months for testing and bugfixing, and two months for release (which they overshot by three months).
https://blog.thimbleweedpark.com/archives.html
At a quick glance: four months for the engine (which they wrote from scratch [1]) and, based on the budget [2], roughly nine months for crowdsourcing and pre-production (setting the overall story and puzzles, deciding on the look of the game, building small proofs-of-concept), seven months for production, three months for testing and bugfixing, and two months for release (which they overshot by three months).
[1] https://blog.thimbleweedpark.com/roadmap1.html
[2] https://blog.thimbleweedpark.com/budget1.html