They’re time-trial levels, where you can race against your own or presumably other people’s ghosts to complete them as quickly as possible. That’s where they evidently think the longevity will be, rather than in extending the plot episodically. But I’m not sure speed-running is for me.
The main basis for my excitement over Mirror’s Edge, apart from the fantastic art, is N. It’s absurdly difficult and endlessly frustrating, but you can retry quickly and there’s enormous scope for finesse. It seems like Mirror’s Edge has a similar process, but I hope speed isn’t the only type of finesse it permits. I never enjoyed trying to maximise my time remaining in N, or speed-run any other game. It was purely about elegance and style.
I tried a speed-run of the first level of Deus Ex once. It went so badly that I actually lost my left leg before I got inside the statue, and I still beat the contemporary fastest time on the Speed Demo Archive.
The bar’s risen quite a bit since then, thankfully, and there’s now a magnificently clever 43 minute run. It turns out grenade-jumping in Deus Ex doesn’t mean what it means in other games, and nano-augmented bunny-hopping is a thing of curious elegance.
This guy has a spectacular way of exiting Maggie Chow’s penthouse suite at maximum speed, never bothers to get his Kill Switch removed, gasses most of UNATCO to get them to open doors for him in their panic, stabs Tracer Tong to shut him up, assassinates Tiffany Savage to save time rescuing her, and pulls off the most laughably improbable escape from the swiftly scuttled Wallcloud. Deus Ex had scope for finesse.
Update: He also survives the most awkward lift ride ever, and there’s something of a surprise ending. I accidentally the whole thing.
Hupdate: Direct download of the super-crisp high quality version of that Mirror’s Edge clip for aesthetes.