Being a teenager’s a tough time. You’re flooded with emotions, often conflicting ones, and you’re not really sure what to make of anything. Watching Class – BBC Three’s new Doctor Who spin-off for young adults – is a similar experience.

The series dropped its first two episodes today, and you’ve got to wonder if the decision to launch with a double-bill was about more than making a big splash. Because you absolutely need to watch both to get a handle on what writer Patrick Ness is trying to accomplish.

The first episode, which bears the poetic and rather lovely title ‘For Tonight, We Might Die’, is utterly bonkers, dashing breathlessly from a creepy cold open to quickfire character introductions to fun peril with monsters to a gory showdown that would make George RR Martin proud.

It’s easy to get swept up in the madness, thanks chiefly to spirited performance from the four young leads. Ness’s script zips all over the place, demanding a huge emotional range from Greg Austin (Charlie), Sophie Hopkins (April), Fady Elsayed (Ram) and Vivian Oparah (Tanya) and these kids knock it out of the park, nailing every single beat.

(So far, their reluctant mentor Miss Quill is a lot more one-note, and while her persistent crankiness and snark make for some good gags – “We are DECORATING!” – it also rather limits Katherine Kelly’s performance. Here’s hoping she’ll get the chance to show a few more shades to the character in future episodes.)

While the show’s roots are showing – not just Doctor Who and the much-discussed Buffy, but also notes of BBC Three’s tragically short-lived The Fades and even dashes of Misfits – there are also some clever subversions of teen-drama clichés (*starting* with the prom?!) and plenty of neat creative flourishes.

In one particularly memorable sequence, a rather cheesy segue into a flashback sequence quickly transforms into something much more witty and knowing – and when it’s firing on all cylinders, Class is energetic, charming, funny and thoughtful.

That said, the series premiere attempts rather a lot, arguably too much. A fast pace is all well and good – in fact, it’s essential to hold on to a younger audience – but at times, ‘For Tonight, We Might Die’ is racing so much that it trips itself up.

Pivotal to April’s series arc is the notion that, after an unfortunate encounter with the monstrous Shadowkin, she now ‘shares a heart’ with their leader – but the scene in which this twist occurs is over and done with so quickly, you might very well be left scratching your head.

A show like Misfits could get away with throwing mad ideas at you and just demanding you accept them, but while Class is occasionally very funny, it’s never as anarchic or self-aware as that show, and you’re left wishing that this more straight-laced series would occasionally take a breath and explore its ideas in more depth.

Then there’s the clash of sensibilities between the brutal and the fanciful. The scene in which Ram’s girlfriend Rachel (Anna Shaffer) is murdered by the Shadowkin is neither a wild sci-fi moment, nor is it horribly grim, but somewhere in the middle. She first disappears in a puff of energy – like a scene out of Doctor Who – and then Ram is sprayed with her bloody remains.

Next, Ram’s subsequent scuffle with Rachel’s killer ends with him having his leg brutally severed, and we fix on his blood-soaked face, frozen in a silent scream.

Then, into the middle of all this, strides the Doctor, a children’s TV hero caught up in bloody chaos, dropping one-liners and waving his sonic screwdriver about. Peter Capaldi is utterly superb (oh, how we’ve missed him!), but his presence just highlights the rather awkward clash of tones at play in the first episode.

When it’s neither too graphic nor too fantastical, Class finds a wonderful middle ground in which it’s simultaneously funny, heartfelt, spooky and vibrant – yes, like Buffy – and happily episode two, with nary a TARDIS in sight, is a lot less mad and a lot more consistent.

A decent stab at a supernatural chiller that also deals in teen angst (again, in the Buffy vein), ‘The Coach with the Dragon Tattoo’ has Ram fighting a creature from another world, and in so doing, finding a new purpose in life after the loss of his old leg scuppers his sporting ambitions.

The episode’s pace is less frenzied, its tone is less haphazard, and already Class starts to feel much more like its own beast. The cast, again, are on top form.

Right now, Class is a bit like a hormonal teen – all over the place, with quite literal moodswings. But also like a teen, it’s finding itself. The biggest takeaway from these two episodes is that we could be in for something really quite special here, once it gets over the growing pains.

The first two episodes of Class are available to watch now on BBC Three.