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