This achievement occurs during Episode 5 - Outatime
After Hill Vallley disappears you'll end up at a farm house, you have the chance to pick up two other achievements, assuming you have the Algae cakes on you.
Do the following:
• Interact with Cactus.
• Walk up to "Scary Mary"s door and over the tripwire.
• Interact with Tripwire.
• Dialog (Edna): Any
• Dialog (Edna): Any
• Interact with Cactus
• Interact with the Tripwire.
• Dialog (Edna): "We spent today together."
• Dialog (Edna): "I brought something for you!"
•
Use Item "Algae Cakes" to equip.
• Interact with Edna (With Algae Cakes equipped.)
•
Green Gobblin' in Back to the Future: The Game - 30th Anniversary Edition unlocked.
• Interact with Cactus.
• Interact with Doc. (If Edna closed the window before you have the chance to do this, just go trigger the tripwire again.
• Dialog (Edna): "It's Emmett Brown!"
• Dialog (Emmett): "Shnookums".
• Interact with Cactus.
•
Use Item "Recording Device" to equip.
• Interact with Edna (With Recording Device equipped.)
• Interact with Cactus.
• Interact with Tripwire.
• Interact with Cactus.
• Walk back by the outhouse.
• Interact with Mop.
• Walk back to the front of the house.
•
Use Item "Mop" to equip.
• Interact with Cactus (With Mop equipped.)
• Walk to the left side of the house.
• Interact with Edna's Hat
•
Use Item Edna's Hat to equip.
• Interact with Cactus (With Edna's Hat equipped.)
• Dialog (Edna): "Tannen".
• Interact with Cactus.
• Walk over to the left side of the house.
• Interact with Saloon Sign.
• Walk over to the right side of the house.
•
Use Item "Saloon Sign" to equip.
• Interact with Outhouse (With Saloon Sign equipped.)
• Interact with Cactus.
•
A Prickly Pair in Back to the Future: The Game - 30th Anniversary Edition unlocked.
• Interact with Clay Oven
• Interact with Burning Stick
• Interact with Outhouse.
Credit to T_l_M_B_0 of PST