Here is the full list of all 32 Celeste achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Climb Celeste Mountain
Complete Chapter 4
Complete Chapter 5
Complete Chapter 6
Collect 80 Strawberries
Collect 175 Strawberries
Get a 1UP
Complete Celeste for PICO-8
Collect the Crystal Heart in Chapter 1
Complete Chapter 1 B-Side
Collect the Crystal Heart in Chapter 2
Complete Chapter 2 B-Side
Collect the Crystal Heart in Chapter 3
Complete Chapter 3 B-Side
Collect the Crystal Heart in Chapter 4
Complete Chapter 4 B-Side
Collect the Crystal Heart in Chapter 5
Complete Chapter 5 B-Side
Collect the Crystal Heart in Chapter 6
Complete Chapter 6 B-Side
Collect the Crystal Heart in Chapter 7
Complete Chapter 7 B-Side
Collect the Crystal Heart in Chapter 8
Complete Chapter 8 B-Side
Complete all C-Sides
Complete Chapter 3
Collect a Cassette
Complete Chapter 2
Collect 30 Strawberries
Complete Chapter 1