I think this part 2 is much better than part 1. its a bit more grounded on the characters, there's a bit less of the fart jokes, but it's still got some good action and comedy.

How terribly designed are those neck braces if they can transmit a massive electric shock over... presumably radio? still, cheap easily resolved cliffhangers are par for the course with DW

On dialogue - there are some great quips from the doctor in this episode. The dialogue from the slitheen is a bit cheesy - but it actually fits well considering they're a rag tag bunch of criminals playing big bad.

The unit computer has "buffalo" as a password. Ugh. this does remind me the bbc had a series of flash games and one of them was this interface that you could play "hacking" into. that was fun. all we get from media tie ins these days is some funny gifs on social media, if we're lucky.

The political play here is actually quite clever. If i can theorise, i would guess getting the earth to destroy itself with its own weapons would skirt around any shadow proclamation rules outlawing their behaviour. Allowing the slitheen to operate a bit more freely and profitably.

That harriet jones being the pm for 3 terms got retconned fairly quickly.