Im not sure it was pretty much instantly released without much playable demos/content before hands (besides from the first look at alice )which then would not be implemented in the game to full release it was 2 months but im pretty sure she drew everything before hands and then build the RPGM game around that
Oct was first sketch look
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Nov was first look of colored pcitures which werent used in the end
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Dec 1st she said all portraits would be ready
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Full game was released february 24
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but mind that she also had to deal with bringing her first game to steam and setting things up (like achievements) which in the end wouldnt work since steam didnt allow her game on steam or something
but in a tweet she stated that she had
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dont know how much of that was only Black paradise but if she keeps working at the pace she is at now plus being more comfortable with RPGM and drawing( having a better workflow) we might be able to see the game finsihed in 5 months max depending on how big of a game she plans on making and how motivated is to put time in the project