Does creating an account reset your progress?

According to this Wikia page, it's just a way to share your score and progress, you should not suffer any reset (or restart, as you call it).

No, it won't. It will keep your icon, it will only change your unregistered name to your account name. :) you should most definetly make one, because that's the only way you can send messages to other people, friend other people, etc.

If you create a new account and merge with an existing save, it'll merge your progress. Of course, double-ups don't count twice (ie. completing the same map on multiple saves).

So if you have multiple game saves and link them all to an account, the game will merge them all into save file that's the best of all game saves (ie. if you completed a map on one save but not another, the best completed result will override the incomplete result on the other saves).

The only time you ever lose your progress is if you either:

• Delete Game Data
• Logout of an Account