Xbox Live’s achievements can vary in quality of implementation, from the most perfunctory bookmarks of progress (King Kong), to the outrageous (finishing Smash TV without dying; 10,000 online kills in Gears), with very few doing what I think is the best thing these can do, in rewarding you for doing those unessential little quests that you take up as a personal challenge.

Climbing the tallest building in the game with your bare hands qualifies – think of the people who managed to scale the temple in Shadow of the Colossus – and this probably qualifies as my favourite achievement yet:

It’s a long climb that takes a bit of planning and lateral thinking, and the reward (10 points aside) is an absolutely spectacular showpiece of the strength of this engine. It’s seriously impressive; a huge draw distance and solid framerate, without the usual caveat of obviously decreased detail. Then, to top it off, there’s another achievement for jumping from the roof and landing in a small pool at the base of the tower. Brilliant stuff. I hope other devs are taking notes.

That sums up what I think of Crackdown so far. I played about seven hours yesterday, running through the first gang on my own and then again in online co-op (every game should have this after Crackdown and Gears), and just messing around with piles of cars and a grenade launcher. Oh, and spending an inordinate amount of time hunting for those agility orbs (250-odd so far, and about 55 hidden ones). God, the orbs! So many! Argh!

The game has been criticised for length, and it did only take me about three hours to finish off the Los Muertos kingpin and all six generals. A third of the main campaign, basically. And that includes several digressions in order to relieve nearby rooftops of their agility orbs. This isn’t a long game, to be sure, but the point isn’t simply to finish it, just as it was with GTA. Those who I’ve spoken to who are as into it as I am spend far more time fucking around, and I’ve enjoyed it for the lack of structure rather than in spite of it.

After the hundreds of free-roaming crime-infested cities that we’ve played around in since Liberty City in 2001, all either po-faced and taking themselves far too seriously or failing to capture the wit of Rockstar’s games, Crackdown is a breath of fresh air. I want to say that GTA IV has a lot to live up to, but that’s going to do its own thing and do it well, as it has over the last few years. Spider-Man 3, however, is going to need to be really special.