Here is the full list of all 20 Ridiculous Marathon (Windows) achievements worth 200 gamerscore.
Get the first level of all powerups
Beat the score: 5.000
Use a magnet and a jetpack at once
Complete a daily challenge
Beat the score: 15.000
Beat the score: 100.000
Beat the score: 500.000
Purchase a main character cosmetic
Purchase a piñata cosmetic
Purchase all main character cosmetics
Purchase all piñata cosmetics
Upgrade all powerups to maximum level
Complete a weekly challenge
Get a mysterious box with the daily challenges
Get x5 multiplier completing misions
Get x20 multiplier completing misions
Crash while using a piñata 10 times
Use the double jump to jump on a log
Get x50 multiplier during a game
Revive three times in the same game