I don't really understand the question. Are you asking what achievements we think are going into the game or what the achievements section's purpose is?
Well anyway here's what achievements I think will be included.
1. Complete the training dream thingy.
2. Battle Felicity
3. Pass zone 1
4. Find the tape player
5. Meet Roald
6. Defeat Baron
7. Pass zone 2
8. Pass zone 3
9. Pass zone 4
10. Complete the game (defeat the mayor) on easy
11. Complete the game on challenging
12. Complete the game n heroic
13. Reach level 5
14. Reach level 10
15. Reach level 20
16. Reach level 30
17. Have 1000 in cash
18. Have 5000 in cash
19. Have 10000 in cash
20. Buy and item
21. Buy 10 different items
22. Buy 25 different items
23. Buy 50 different items
As for it's purpose, just like any achievement section, it probably won't do anything except keep track of what you've done.