You can definitely see Graham Williams influence in this episode, lots of humour, Romana's regeneration especially. There's a place for humour in Doctor Who, and in Part 1 I think they get the balance right, those that harp on about canon, I urge you to look here, they literally make it up as they go along.
I loved Mary Tamm, but Lalla is equally brilliant as Romana, she starts off so well. The first of her many outfits, she looks brilliant as a contrast to Tom. She gave Romana a very different personality and truly did inject a new interest in the character.
To this day I'm still not sure what to make of the Movellans, they look very disco, all they need is a disco ball and Donna Summer's 'I feel love.' Parts of their ship look good, the large screen in the background looks great, the guns and headsets perhaps not so.
The episode clearly looked to build on the huge success that came from Genesis of the Daleks, I know this episode is often poorly regarded in many fan circles, but I think it starts off really well. I really like the opener, there is lots going on, it's wonderfully atmospheric, and the cliffhanger makes you want to see what happens next.
Part 1, good, 7/10