Hey, cute game. As a heads up though, it looks like there might be a bug or two.
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After I inserted the password in the shop, I *think* I solved the puzzle, but nothing happened. Potentially related or a separate issue is that even though I acquired enough coins, I couldn't purchase the next building after the factory.
Puzzle solutions that I tried were covering only the X squares with the tiles and covering only the non-x squares with tiles - neither of which seemed to change anything.
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If this issue is addressed or I just misunderstood, please let me know as I definitely want to continue playing.
Thanks for reading and take care!