Pretty cool, I combined it with the Key-Lock-style adventure from https://thenwdm.itch.io/alone-together-1 and have a lot of fun.
Just a side remark that the root of the sum of the 2-digit numbers is the same as just summing all the digits (and taking the root). I think it is still unpredictable enough for me that way but it makes it a bit easier to calculate to my mind.