The only thing to note here is that you must reach level 10 EXACTLY: if you get enough experience to bypass level 10 entirely and hit level 11, you will not earn the Achievement,
as happened to me. If you want to be sure you don't overstep it, use Ace Annihilates's Google Sheet from the ONE HUNDRED! Achievement:https://docs.google.com/spreadsheets/d/1DHfhV0DybXTsMj0E6ZeJ...
because it's a pretty tiny window to get through if you're knocking out some of the larger challenges easily.
Fortunately, if you DID skip level 10, you can still get this one through these steps, assuming your save data is backed up to Xbox Live:
1) Close the game, and go into Settings -> Network settings -> Go offline.
2) While offline
, go into Settings -> System -> Storage
, and for your local storage device, select View contents.
Highlight THPS1+2, hit the Menu
button, select Manage game and add-ons
. Go down to Saved data
and delete the saved data for your account.
3) While still offline,
load up the game. Knock out enough challenges to get between 2,520 - 2,900 cumulative experience, which will almost certainly take very little time or effort; it took me probably under a minute on Warehouse just doing big combos with special tricks and paying little attention.
4) Before actually reaching
level 10 - i.e. before claiming the Challenge rewards to actually add those experience points - go back online.
Then claim them, and the Achievement will pop.
5) Close the game, re-open it, and you'll be prompted to choose either your local save data (where you're at level 10) or your online save (whatever you were at before.) Obviously pick the latter if you don't want to start over.
So if, like me, you skipped over Level 10 and weren't granted this Achievement and have also never messed around with local vs. cloud saves before, there is
a slightly annoying, but ultimately relatively straightforward, workaround for it to start over without really[/] starting over. And fortunately, hitting level 10 is obviously incredibly easy in itself, so the entire process can probably be done in like five minutes.
Hopefully they do eventually patch this by just setting the Achievement to pop if you reach any level past 10 or something.