IMO, yes it is complete enough (note: I only went as far as the assembler challenges, I'd done enough assembler beforehand). But I did build a general purpose computer from NAND gates up.

Development still appears to be ongoing on Discord, which is quite active. I think the dev may have bitten off more than they could chew with their last patch promise: https://www.youtube.com/watch?v=38cKko7sViw