Here is the full list of all 14 Classic Snake Adventures achievements worth 1,000 gamerscore.
Complete all the game with any score.
Complete all the game with 3 stars.
Eat the yellow face item.
Complete world 4 - Ice.
Complete world 3 - Village.
Complete world 2 - Swamp.
Complete world 1 - Forest.
Export your hiscore and see the leaderboard.
Reach and win the first boss.
Complete and get one bonus.
Get your first 10000 points.
Finish a round with 4 hearts.
Make the snake 20 pieces long.
Finish any round with 3 stars.