There is over 60 Combo cards in game, most of them you can get when you level up. For the achievement, you need only 50.
You should get level 50 and 34 combo cards.
You will get 8 combo cards for completing all single player challenges in sandbox mode.
After these, need less than 10 combo cards, and you will get achievement when you collect all movie posters (Video bellow).
Leveling Up Combo cards
1. Drill Bucket - Level 3
2. I.E.D. - Level 5
3. Pole Weapon - Level 6
4. Air Horn - Level 7
5. Weed Tendonizer - Level 8
6. Bouncing Beauty - Level 10
7. Gem Blower - Level 12
8. Electric Chair - Level 13
9. Blitzkrieg - Level 14
10. Ripper - Level 15
11. Cryo Pod - Level 17
12. Dynameat - Level 19
13. Heliblade - Level 20
14. Fire Spitter - Level 22
15. Sticky Bomb - Level 24
16. Pegasus - Level 26
17. Defiler - Level 27
18. Hail Mary - Level 29
19. Electric Crusher - Level 31
20. Shocker - Level 32 (Thanks to SPARTANKING8675)
21. Knife Gloves - Level 33
22. Roaring Thunder - Level 34
23. Super Slicer - Level 35
24. Spear Launcher - level 37
25. Handy Chipper - Level 38
26. Tesla Ball - Level 39
27. Parablower - Level 40
28. Flaming Gloves - Level 41
29. Infernal Arms - Level 42
30. Super BFG - level 44
31. Porta-Mower - Level 46
32. Driller - Level 47
33. Lightning Gun - Level 48
34. Auger - Level 49
35. Laser Rifle - Level 50
Sandbox Challenge Combo cards (Sandbox mode, earn gold medal to get combo card)
36. Boomstick - Single-player challenge: Rooftop Massacre (0 kills, Atlantica Casino roof)
37. Fountain Lizard - Single-player challenge: Crowd Pleaser (300 kills, Slot Ranch Casino, on the stage)
38. Saw Launcher - Single-player challenge: Chop Suey (350 kills, South Plaza, Silver Strip entrance)
39. Beer Hat - Single-player challenge: Thirst Quencher (2,000 kills, Atlantica Casino)
40. Molten Cannon - Single-player challenge: Burn the Bodies (4,750 kills, Yucatan Casino)
41. Electric Rake - Single-player challenge: Lightning Never Strikes Twice (4,800 kills, Fortune Park, Atlantica Casino entrance)
42. Money Hacker - Single-player challenge: One Armed Bandit (8,005 kills, Slot Ranch Casino)
43. Reaper - Single-player challenge: Double Trouble (9,500 kills, Yacatan Casino, Shoal Nightclub)
Movie Poster & Miscellaneous Combo cards (Video bellow)
44. Tenderizers - Movie Poster - Blood Round 4 poster in Royal Flush Plaza, near Americana Casino entrance
45. Decapitator - Movie Poster - Kangaroo Apocalypse poster in the Americana Casino, in hallway to restrooms
46. Blambow - Movie Poster - Revenginator 7 poster in Food Court, near Cucina Donacci
47. Freedom Bear - Movie Poster - Untitled poster in Yucatan Casino, right outside the restrooms
48. Freezer Bomb - Movie Poster - Palisades mall 2nd floor, between Brand New U (P203) and Ned's Knicknackery (P204) (Thanks to SPARTANKING8675, ISNT IN VIDEO)
49. Holy Arms - Movie Poster - Pit Viking Poster in the Atlantica Casino, near the craps tables
50. Paddlesaw - Movie Poster - Paddle Party Massacre poster in the Silver Strip, near the Slot Ranch Casino entrance
51. Laser Eyes - Movie Poster - Uranus Invaders! poster in Uranus Zone, next to U123
52. Laser Sword - Movie Poster - Paradice Strip, in Paradice Platinum Screens (S104) (ISN'T IN VIDEO)
53. Super Massager - Movie Poster - Massage-O-Tron 3000 poster in South Plaza, inside the under-construction American Undies store.
54. Zap 'N Shine - Make Weapon 1st time- Build the Zap N' Shine combo weapon (Floor Buffer (Yacatan casino, outside of maintenance room near rock where you found Snowflake) + Electric Prod (Yacatan casino, in the maintenance room behind the Snowflakes rock))
55. Wingman - Make Weapon 1st time - Build the Wingman combo weapon (Nectar (Mix Apple+Apple in blender, blender and apples are found in Rojo Diablo Mexican Restaurant (F106 Food Court) + Queen (Random when killing zombie, small flying insect)
56. Burning Skull - Miscellaneous - Watch the movie "Paddle Party Massacre" in Paradise Platinum Screens (Platinum Strip, every day 9.00pm to 10.30pm)
Survivor, Psychopath & Miscellaneous Combo cards
57. Spiked Bat - Miscellaneous - Earned after returning to Royal Flush Plaza once you've started Case 1-2
58. Molotov - Psychopath - Defeat the psychopath Chuck Greene (Fortune Park, Day 1 3.00pm to Day 2 8.30am (People Like Us))
59. Power Guitar - Survivor - Floyd (Silver Strip, on the stage, Day 2)
60. Flamethrower - Psychopath - Defeat the psychopath Slappy (Palisades Mall, Day 2 12.00pm to Day 3 3.00am (Everyone Knows Slappy))
61. Plate Launcher - Survivor - Wallance (Palisades Mall, Kokonutz Sports Town. Day 3 6.00am to 12.00am (Tape It or Die))
62. Rocket Launcher - Psychopath - Defeat the psychopaths Roger and Reed (Atlantica Casino, Day 4 12.00am to 9.00pm (The World's Most Dangerous Trick))
63. Snowball Cannon - Psychopath - Defeat the psychopath Evan (Platinum Strip, Day 3 9.00pm to Day 4 7.00am (Snow Job))
64. Blazing Aces - Survivor - Lance (Palisades Mall, Kokonutz Sports Town. After military arrives)
65. Exsanguinator - Survivor - Wallance (Palisades Mall, Kokonutz Sports Town. After military arrives)
If you vote negative, comment and tell me why, so i can edit this. Thanks
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