Here is the full list of all 24 Alfonzo's Arctic Adventure achievements worth 1,000 gamerscore.
Collect 50 Gold Fish
Collect all Gold Fish
Collect 10 Gold Fish
Collect 30 Gold Fish
Collect 20 Gold Fish
Defeat Perfect Yuck
Find a Secret Path in Episode 6-7
Defeat Yuck
Defeat the Angler
Find a Secret Path in Episode 5-14
Find a Secret Path in Episode 5-1
Defeat the Easter Bunny
Find a Secret Path in Episode 4-2
Find a Secret Path in Episode 4-8
Defeat the Evil Snowbeast
Find a Secret Path in Episode 3-6
Find a Secret Path in Episode 3-12
Defeat Battsu the Maturity Elf
Find a Secret Path in Episode 2-8
Find a Secret Path in Episode 2-3
Defeat Samsuin
Find a Secret Path in Episode 1-5
Find a Secret Path in Episode 1-3
Collect a Gold Fish