Edit: The achievements are now live. People who have yet to play the DLC can now play without any worries. Those of you who had unlocked the achievements before they were uploaded to Xbox.com will want to follow the steps below to rectify the issue.
Two years ago, Doritos Crash Course was announced as the winner of the last Doritos Unlock Xbox competition. Unlike the other two Doritos games, Crash Course got a bit of a rough initial reception due to the fact that not all of the achievements were stupidly easy. Those players who stuck with the game found a fairly enjoyable platformer based on a Wipeout style obstacle course. If you like your achievements to have a bit of a challenge to them, you'll be interested in the new DLC for the game.
Winner of the Unlock Xbox competition and with over 3.5 million worldwide downloads, Doritos Crash Course returns with new level pack featuring 10 new courses filled with unique challenges and puzzles. Bounce above the glitz and glamour of Las Vegas and sprint through the historic sights of London to prove once more, who is the fastest in the world’s leaderboards. As well as new achievements for even more gamerscore, we also include new versions of the Japan levels so you get even more chance to unlock all the achievements. We’d like to thank you, the community, for helping make Doritos Crash Course into an XBLA phenomenon."Doritos Crash Course City Lights" adds three new achievements worth a total of 50G 100G, but at the time of writing these are not yet added to Xbox.com -- check out Microsoft's XBLA blog for the achievement list, even though the point values are wrong. Those of you who unlock the achievements now will notice that they are not being added to your gamerscore or achievement total and I would advise holding off from playing the DLC until the achievements are added properly. Unfortunately, those of you who unlock the achievements beforehand will have to recover your gamertag and then earn the achievements again for them to be added to your gamerscore.
Unlike the game, the DLC is not free; it costs 160 MSP and can be downloaded from here. If you'd like to try out the content before deciding on a purchase, download the FREE trial instead.
We've got the full list of Doritos Crash Course achievements - check the list for guides to unlocking them.