Flatline is rad as hell.  It's a very fun episode where Clara gets to take centre stage in a way that felt both natural and much-wanted.  I wish I liked her as a companion more.  Jenna Coleman is clearly an incredibly talented actor, but often this show felt like it had very little for her to do or even enough space for her to be a real character other than just as a sounding board for the Doctor.

Yet here she gets to take the lead in solving this mystery as a small part of London becomes terrorized by the Boneless.  She really drives the story forward in a cool way, using the sonic and leading the other survivors against these monsters.  It's brilliant and not only one of her better episodes, but also one of the better episodes in general to really rely on its companion characters.

The Boneless that confront Clara and the Doctor are mysterious in the best possible way at the start of this episode.  I like how their nature as extra-dimensional invaders is expressed in them being essentially flat.  It made for a lot of creepy scenes and the Boneless felt very powerful, especially as they were able to affect even the TARDIS.

One thing that bothers me, and it is mostly minor, is that the Boneless are only named at the very end.  It might just be my Canadian ears, but when the Doctor finally names them, a big moment the whole episode feels like it is building up to - I actually can barely make out him saying "Boneless."  Maybe it's Capaldi's accent, maybe it's just the sound mixing of his line is too low against the big sound effects used in that moment, but either way it blunts the hell out of that scene's effectiveness.  It's a great episode overall though.  I like the characters who were all pretty distinct.  Rigsy was a fun companion of sorts for Clara, and the cop at the beginning was good too - what happens to her is quite brutal for Doctor Who standards and it gets into the episode's more distinct and memorable qualities - the Boneless are true menaces that feel dangerous and scary - I love it!  That one supervisor guy was a little annoying, though.  He felt unnecessarily antagonistic and blemishes and otherwise excellent episode.  I definitely enjoy revisiting this one, too.  Top-tier stuff overall.

This story is a start to finish banger. Unique villains, and Jenna Coleman gets to be the Doctor and does a heck of a job with it, even getting her own companion. It's unsettling, exciting, and features one brilliant resolution.

“I’m the Doctor, and I’m the man who defeats the monsters.” What an amazing moment. It feels as though the Doctor arrives on the scene with a renewed sense of purpose. He’s been kept away from the action for much of the story, but here he makes up for lost time, with a clarity about who he is that has sometimes been missing from this series. While the moment is slightly undermined by the continuation of the “Am I a good man?” theme, which feels a little overused at this point - that’s a minor issue in an episode brimming with charm, fun, and energy.

The TARDIS changing size, the Doctor advising only through his voice, and using Clara as his eyes and even physically moving the mini TARDIS with his hand - these moments are absolutely hilarious and heart warming. The villains, the graffiti-monsters or “Boneless”, are a fascinating concept, adding a distinct and creative menace to the story.

What stands out most is Clara. She absolutely shines in this episode, stepping into the Doctor’s shoes and taking the lead. It’s a fantastic opportunity for her character, and she makes the most of it, proving just how capable and compelling she is. Few companions get an episode like this, and at no point does it feel like the Doctor’s absence diminishes the energy of the story.

This is a truly compelling episode, filled with originality and character. Jamie Mathieson has delivered something special two weeks in a row, raising the standard of the series and creating a story that stands out as particularly memorable.

This episode has an interesting and unique concept which got me hooked right from the start. Clara really shines in this episode, and the plot is strong and well-paced. The episode's resolution feels clever and sensible. It's by no means my favourite, but it's good.

Another very good episode. Enjoyed last week a little more but loved the idea of The Boneless and they could easily return too. The resolution wasn't much but that didn't spoil things too much. Very interested to see where The Doctor and Clara's relationship is going, the character development has been terrific.