This game heavily relies on timing, so a text guide would not be advisable.

Levels 1-10
Level 1. 0:01
Level 2. 0:25
Level 3. 1:01
Level 4. 1:30
Level 5. 2:03
Level 6. 2:13
Level 7. 2:35
Level 8. 3:18
Level 9. 4:13
Level 10. 4:46

Levels 11-20
Level 11. 5:17
Level 12. 5:37
Level 13. 6:27
Level 14. 6:57
Level 15. 7:39
Level 16. 8:29
Level 17. 8:58
Level 18. 9:52
Level 19. 10:41
Level 20. 11:20

Levels 21-30
Level 21. 11:59
Level 22. 12:27
Level 23. 12:58
Level 24. 13:45
Level 25. 14:01
Level 26. 14:43
Level 27. 15:21
Level 28. 15:50
Level 29. 16:24
Level 30. 16:41

Levels 31-35
Level 31. 17:25
Level 32. 17:46
Level 33. 18:20
Level 34. 18:46
Level 35. 19:28*
Level 36. 20:11

*Pushing a block into a hole, then trying to walk over it creates interesting results.