Here is the full list of all 22 Seasons achievements.
Complete Autumn
Complete Winter
Complete Spring
Complete Summer
Finish Seasons
Jump 100 Times Total
Jump 500 Times Total
Play Seasons for 2 Hours Or More
Complete The Autumn Speedrun Without Dying
Complete The Winter Speedrun Without Dying
Complete The Spring Speedrun Without Dying
Complete The Summer Speedrun Without Dying
Complete The Gauntlet Speedrun Without Dying
Die 50 Times
Die 100 Times
Find The Cat Room
Find The Dog Room
Jump 1000 Times Total
Collect Your First Shiny
Collect Half The Shiny Stuff
Collect All the Shiny Stuff
View The Credits