This is pretty sick solution! Good job!

Thanks for the compliments and the encouraging words, glad you enjoyed the Series :D Don't forget to check out other Kata I have authored ;)

I have to say I love the series! I have finished all four of the tasks and they all were cool. Anyway I don't know if it is just me or Boolfuck interpreter is much harder than brainfuck interpreter even though they are both rated as 2 kyu. Anyway thanks for the tasks!

Well I also thought that the whole loop was supposed to be considered as 1 iteration and lost some time implementing it (actually it was the hardest part of implementation for me) and then I realised it's just not how it was supposed to work.
I think you could clarify that in description as it seems it's might be a common mistake :)