i have seen several guides for this and all i ever could find on it was you just have to get everything, my first run through i was short a lot of credits, second time was a speed run third time i missed a pickup somewhere so on my fourth time through i made this list of how i picked up each powerup and how much each one cost hopefully it helps out more then just hey get everything
1. plasma gun ammo 1/6 - 200
2. plasma gun ammo 2/6 - 300
3. plasma gun ammo 3/6 - 400
cluster rifle - 1500 (gold disk)
4. mooch transmitter - 200
5. cluster rifle ammo 1/6 - 200
6. plasma gun ammo 4/6 - 500
electro whip v2 - 1000 (gold disk)
7. cluster rifle ammo 2/6 - 300
8. cluster rifle ammo 3/6 - 400
9. plasma gun ammo 5/6 - 600
10. darwin health 1/5 - 200
11. cluster rifle ammo 4/6 - 500
12. mooch transmitter - 250
nanohacker - 1700 (gold disk)
13. nanohacker ammo 1/6 - 500
14. cluster rifle ammo 5/6 600
15. mooch health - 1/3 - 100
shot bolter - 2000 (gold disk)
16. mooch transmitter - 300
17. plasma gun ammo 6/6 - 700
18. cluster rifle ammo 6/6 - 700
19. nanohacker ammo 2/6 - 700
20. shot bolter ammo 1/6 - 200
21. darwin health 2/5 - 300
22. shot bolter ammo 2/6 - 300
freeze gun - 2500 (gold disk)
23.shot bolter ammo 3/6 - 400
24. freeze gun ammo 1/6 - 200
25. mooch transmitter - 350
26. freeze gun ammo 2/6 - 300
27. nanohacker ammo 3/6 - 1000
28. freeze gun ammo 3/6 - 400
29. shot bolter ammo 4/6 - 500
cluster rifle v2 - 1500 (gold disk)
30.darwin health 3/5 - 400
31. freeze gun ammo 4/6 - 500
32. shot bolter ammo 5/6 - 600
33. freeze gun ammo 5/6 - 600
34. nanohacker ammo 4/6 - 1400
35. mooch transmitter - 350
36. darwin health 4/5 - 500
37. mooch health 2/3 - 150
38. nanohacker ammo 5/6 - 1900
39. shot bolter ammo 6/6 - 700
flame thrower - 100 (gold disk)
40. mooch health 3/3 - 200
41. flame thrower ammo 1/6 - 200
42.flame thrower ammo 2/6 - 300
43. flame thrower ammo 3/6 - 400
44. nanohacker ammo 6/6 - 2500
nanohacker v2 - 100 (gold disk)
45. flame thrower ammo 4/6 - 500
46. mooch transmitter - 350
47. flame thrower ammo 5/6 - 600
48. freeze gun ammo 6/6 -700
49. flame thrower ammo 6/6 - 700
50. darwin health 5/5 - 600
Updated 01-12-2016 07:32 PM
i dont think this was all that much of a grind as i have not even hit 25 wins on the daily missions yet my first run through of the game i played till i got a win in each level or at least 1 level with 10 win streak to get gold to unlock all the levels then i started back on point levels and played each level till i had gold on each level then i moved to eraser level and played till gold on each level and started rope levels and got to level 23 before i popped the achievement
this is quite tricky but its not really that hard it does not have to be 800 points in 1 twins mode as long as its in 1 session multiple twins modes will still count for this