Here is the full list of all 28 Tumblestone achievements.
Solve a 3-star Practice Puzzle.
Complete World 1.
Complete World 2.
Complete World 3.
Complete World 4.
Complete World 5.
Complete World 6.
Complete World 7.
Complete World 8.
Complete World 9.
Complete World 10.
Complete World 11.
Complete the Story Mode.
Solve Puzzle 2-8 using 44 moves.
Win an online Puzzle Race match.
Win a Puzzle Race match using a modifier.
Win an online Battle match.
Win a Battle match against 3 Nightmare bots.
Win an online Tug of War match.
Win a Tug of War match against 3 Nightmare bots.
Get a score of 333 in Heartbeat.
Empty the board in Heartbeat.
Get a score of 500 in Infinipuzzle.
Get a score of 333 in Infinipuzzle using a modifier.
Get a score of 1,234 in Marathon.
Empty the board in Marathon.
Reach rank 25.
Complete 25 quests.