SONIC UNLEASHED

note: Having maxed-out characters will help you out with this (especially the night trials).

As with the other continents, you need to complete the following to unlock this achievement:

Hedgehog:
Time
Rings
Enemies

Werehog:
Time
Survival

All of the above have three levels.

For the Hedgehog time trial, follow the below video to the best of your ability and make sure you have the Lightspeed Dash upgrade.
There are 514 rings in the day level. There are well over 100 rings before the first checkpoint, so you shouldn't have any trouble with the rest of the level if you don't get hit.
After you take out the two clusters of enemies shortly before the first checkpoint, get rid of all enemies you see and the Enemies trials will be a piece of cake.
You're going to need to be extremely cautious for the Survival trials. Level 1 starts you out at full health, level 2 drops it down to 1/3, and level 3 only gives you 1/6 of your health (note: this is assuming you're playing with maxed Life). The other video at the bottom of the page shows you an ideal way to make it through the level safely, as well as a route you can use for the Time trials.

You need to complete all of the Mazuri hot dog vendors challenges for both Sonic and the Werehog:

Sonic:
Time Trial, Levels 1,2 and 3
Ring Trial, Levels 1,2 and 3
Battle, Levels 1,2 and 3

Werehog:
Time Trial, Levels 1,2 and 3
Survival, Levels 1,2 and 3

It takes a while but isn't too hard