Yes my attempt at maintaining surprises means I didn't mention the TARDIS interior reveal.
Sorry, going to go a bit detailed here, feel free to skip this bit!
This story reveals a brand new TARDIS console which is slightly smaller than the old one and with a slightly different shade of green. (It was only green in the black and white days as it looked more 'white' and wouldn't flare on the 405 line cameras). New central column as well also in green that sadly doesn't rotate as well as rise up and down. It has been argued that the console is Hartnell's refurbished but photo comparison shows that although all the levers and dials are in the same approximate positions, they don't quite match. Interestingly it's unveiled covered in junk and wiring, showing the Doctor's desperate attempts to fix it. The budget couldn't run to new walls or fresh paint so the roundelled walls show a tint of yellowing paint and a small amount of what seems like mould in a corner. The scanner has been diminished down into a roundel and without realising it, beginning a trend that now features in Matt Smith's TARDIS (much bigger roundel there though.)
Still an attempt at referring back to the black and white days as the eagle plinth seen since the first episode is back again and if memory recalls, one of the chairs too. Also note that instead of showing the area outside the TARDIS when the interior doors open, it shows a roundelled walled lobby.
The Master's not impressed though when trying to get it going, "Underpowered, overweight...a museum piece. May as well try to fly a second hand gas stove!!"
The Master basically does the Doctor's work in episode 3, trying to stop Axos (albeit under duress) and gets the TARDIS almost repaired.
I love the shot of the TARDIS on the back of the lorry although the Master's impression of a General is appalling - how come Benton didn't spot it??
The plot is beginning to sink under its weight here, Axos is about to absorb all the power of Earth but can't time travel without the Nuton Complex power that it will absorb anyway.
Stars of the future - we had Tim Pigott-Smith, Mr It Ain't 'Alf Hot Mum and now Charlie Slater from Eastenders who had a blink or miss it moment as a UNIT soldier zapped by an Axon.
Delgado really is carrying this story and shows why he has so many fans, just as Troughton kept the Krotons on the boil. The music meanwhile would give early 70s primitive synthesisers a bad name if they hadn't got one already.
Still, a think episode four is a good end to the story in some parts so I'll comment on that later.