The second half is ridiculous. The Keller Machine just starts jumping around the prison for absolutely no reason whatsoever. It's just filler.

And doesn't Jo essentially shoot someone at one point? The justification appears to be "well, they're prisoners anyway".

This is a story that I really don't get the hype around. The only interesting character (not including the regulars) is Chin Lee, and she vanishes off the face of the earth after episode 3.

This is one I remember as being a bit of a mess. Interesting premise with the Keller Machine, but the overall story just doesn't quite land right.

It did not need to be six episodes. Plus, it really irritates me that we never get any sort of satisfactory explanation for what the thing inside the Keller Machine is or how the Master acquired it while he was trapped on earth.