Hm I see two challenges here:
Function naming
While there is no 100% strict rule, I think one conclusion from The current state of function naming style is that it is either meshedcase (but mainly in Base) or snake_case, but you seem to follow something else.
Variables too often in global scope
I did not check many of the problems but it seems in a solution like Solution - Build SH*T with Julia you set a bad example by nearly always using global constants. I think that is not something one should do in Julia.
Besides that one I looked only into Problem 2 (so the first problem?!) Problem - Build SH*T with Julia where you specify in the problem that matrix multiplication should return an Int? That is wrong and super misleading.
I fear I have to agree with Tamas here. I also do not like that the Book title tries to be a pun – and one with a swear word.