I can't find anywhere how either of the first two games did for sales. I'm guessing they must have done ok to warrant multiple sequels, being that it is a niche title I'm guessing the numbers don't need to be huge. Is it just not tracked well, or were most of the sales digital?
I guess i'm just interested on what the sales for a niche title like this needed to consider it a success and worthy of making it into a series.