Here is the full list of all 15 Nippon Marathon achievements.
Completed Story Mode with J DARWIN
You traversed 200 meters in LOBSTER mode
You were declared the smelliest - Get away from me!
You chose Snuguru 20 times. (Player 1)
100 Shiba Inus have been startled!
Whoa! You finished a single race with 100% popularity, that is incredible! (Player 1)
Boo! You finished a Single Race with 0% popularity, you suck! (Well done) (Player 1)
Well done, you went to the effort of finding a page from Wedy's Travel Guide and then, well, you ate it.
Wow! First place in a Half Marathon - You're half awesome! (Player 1)
Completed Story Mode with Snuguru Maestro
Completed Story Mode with Nishibori
Completed Story Mode with Zenbei
Whoa! You hit 3 strikes in a row in Go-Go Trolley Bowling!
You finished a Full Marathon, what impressive cardio!
Collected all Wedy Pages and became a Legendary Backpacker