Route A or Route B
Stamp Collecting - 1,150 EXP, 5,000G, 5x Broken Circuit, Fast Cooldown +3, Precious Earrings
I started this one near the end of Route A before meeting Pascal at the Abandoned Factory, but I'm sure it can be done much earlier. Speak to the machine receptionist at the entrance and he tells you to collect stamp cards to be exchanged for a deluxe prize. There are 10 of these all over the park and all of the locations are marked. If you end up missing one, it's likely the one from the backstage area. There's an elevator off to the right of the stairs leading to the room with the stage. Take that down to a new area and destroy all the machines that want to "play".
Route B
Game Dev Machine Lv 1 - 1,300 EXP, 5,000G, 5x Rusted Clump, 3x Small Gear, Melee Attack Up L, Ranged Attack Up L, Medium Recovery
This becomes available at the backstage area after you defeat the boss in the Amusement Park. The game creator machine needs a Tri-color Cable which can be easily harvested from the enemies at the entrance of the park itself. Bring the item back to the client and test his game. Hug the left wall to until you go right through it.
Game Dev Machine Lv 2 - 1,430 EXP, 10,000G, 3x Pristine Cable, 3x Severed Cable, 3x Titanium Alloy, Melee Defense Up L, Large Recovery
Given by the same client after you complete Game Dev Machine Lv 1. This time he needs a Four-Color Cable which you must get by destroying enemies at the designated spot in the Abandoned Factory. Give the item to the game creator and test his game for bugs.
Game Dev Machine Lv 3 - 1,900 EXP, 10,000G, 3x Rusty Bolt, 3x New Bolt, 3x Memory Alloy, Hijack Boost +4 Chip, Stun +4 Chip, Heal Drops Up +4 Chip, Combust +4 Chip
This the last of the game creator's errands and unlocks after completing Game Dev Machine Lv 2. Bring him a Five-Color Cable from one of the enemies in desert section of the City Ruins, then give the game another go to find bugs.