It feels like an absolute eternity since The Christmas Invasion brought Tennant's Doctor properly to our screens, and in that time the anticipation for series two has been at fever pitch.

Weirdly, though, somewhere along the way that anticipation seems to have passed New Earth by a bit. Maybe it's because of all the pre-broadcast mutterings of it being a decent episode, but not an amazing one, and certainly not one that feels like a season opener (indeed, if rumours are to be believed, it was only late on that the decision not to switch it around with Tooth and Claw was taken). Maybe it's because of the three-minute long trailer that aired on BBCi and quickly hit the torrent rounds this week, featuring extended clips of the first half of the series - Tony Head being brilliant, Sophia Myles being lovely and the Cybermen being ABSOLUTELY BLOODY TERRIFYING - with clips from New Earth notable by their absence. As it is, then, we've been left in the curious situation of sitting down to watch the first episode of the new series, but almost waiting for it to be over and done with so that we can get on to the series' real meat.

But what, after all that, was it actually like? Well, unsurprisingly, it was a decent episode, but not an amazing one, and certainly not one that felt like a season opener. For starters, an excellent, scene-setting pre-credits montage was immediately ruined by the gushing nature of the Doctor and Rose's conversation upon leaving the TARDIS. I'm not one of these fans who cowers at any hint of sexuality on the Doctor's part - I'm very interested, for example, to see a proper good old fashioned love story later in the series with the ever-reliable Stephen Moffat's Girl in the Fireplace. But I do feel that somewhere along the way, Russell Tee has got a bit swept up in the notion of the Doctor and Rose as a "couple". I really liked that in the first series, people were constantly assuming that they were, but that instead there was a deeply platonic love and friendship between them. Here, though, with the dashingly indiehandsome Tennant at the helm, and Piper in particularly delectable form, there's rather more sexual chemistry than seems necessary. Not because the Doctor should be some weird asexual figure - how often do people forget that the very first thing we found out about him back in 1963 was that he had a granddaughter? - but simply because it shouldn't ever really become the focus of the show. At times, it felt like that was all New Earth was about.

What it was also about, though, was some guff about cats, zombies and disinfectant in a hospital. Certainly not RTD's strongest ever plot - although, just like Rose last year, you could argue that this ep was more about being swept up in the ride than anything else. Still, though, some things just didn't hit the mark. It was a shame to see Cassandra-in-skin-form disappear almost as quickly as she reappeared - a combination of those scenes and the brief party scenes meant it was little more than a cameo for Zoe Wanamaker, with the rest of the ep consisting of Piper and Tennant's (admittedly quite funny) impersonations of her. It also didn't feel anything like as sinister as the "TARDISode" (ugh) that preceded it had made out. The explanation of the cat nurses' plottings was a little on the vague side (I somehow think that "every disease in the galaxy" would do a bit more than give you a few boils on your face), the resolution was clumsy (explain to me how an intravenous solution can cure you by being poured over you?) and the "softening" of Cassandra felt a little uneasy in the context of the killings she was responsible for in The End of the World. Her closing scene was a bit unsatisfying, too - I'm not the first to point this out, but it really is quite strange that she'd so vividly remember the last time she was told she was beautiful, but not the fact that the person who told her so died in her arms shortly afterwards. Furthermore, it's hard to feel particularly moved by the prospect of someone telling their self that they're beautiful.

That said, it's not like there wasn't plenty to commend, nor indeed that the episode wasn't enjoyable. At the head of it all is Tennant, giving the impression that the scripts could be far more lacklustre than this and he'd still make it incredibly watchable. Every Doctor takes time to settle into the role, and in retrospect that could even be said about Eccleston, even though many said at the time they felt he nailed it from the beginning. Tennant, however, is an absolute natural. While someone acutely aware that playing the Doctor first and foremost means you can bring more of yourself to the role than you can with most parts, he's also the first in a while to show an awareness of what's gone before him. While the Doctor's personality changes with his body and face, it's easy to forget (especially for a new viewer) that he is still, at heart, the same character. Tennant shows sparkles of his predecessors at the same time he makes the role his own, and effectively captures the combination of wide-eyed, whisk-you-away wonder and steely, in-control confidence that the character needs to have.

In terms of the look of the thing, it's easy to grumble that we didn't see enough of New Earth or New New York, and you can see the point there. On the other hand, we mustn't assume that, just because Who is now a viable success, it's going to suddenly be on a Hollywood budget. And as a more lightweight episode in terms of budget - comparable to, say, The End of the World or The Long Game - it still looked a damned sight more expensive than this time last year. Put it this way - if the "lesser" episodes can look like New Earth did, then what kind of treats are in store once we get to Rise of the Cybermen? I liked, too, an increased role for the Face of Boe - it was good to hear him "talk", finally, and I'm not grumbling so much as some folk at the fact that his "big secret" wasn't revealed and that he didn't, in fact, die. To be honest, I like the idea of him being someone that will pop up from time to time as the years go by - it's always nice to have something new added to the mythos.

At the end of the day, while this may not have been the strongest episode ever, it's hard to feel any real sense of disappointment so long as you remain in the frame of mind that this is as weak as the new series is likely to get. There's a quite insane amount of crowd- and fan-pleasing goodness to look forward to in the coming weeks; and, while a massive "we're back" first episode would have been nice, in hindsight I suppose I'd rather get the more lacklustre episode out of the way first. While New Earth will be as good as forgotten by this time next week, given the (hopeful) quality of Tooth and Claw, it was by no means an embarrassing disaster. We've begun on safe, familiar ground - now it's time to really take off.