For this achievement you'll need to collect 50% of all pins in the game. Naturally, you'll obtain this achievement on your way to collecting all pins for
Take note that a couple of pins are missable. You don't have to collect them for this achievement, but you'll need them to obtain the achievement for collecting all 176 pins. The two missable pins are listed below:
- In Yen Sid's Lab (tutorial level where you obtain the brush), paint the painting displaying a chest at the very end of the stage. Once you make your way through the painting, the pin is inside the chest.
- In the Dark Beauty Castle (the level following Yen Sid's Lab), after you fall through the floor and make your way across some thinner, there is a large room with several machines in it. Once Oswald has powered two of the machines, you'll be prompted to either fix or destroy the third machine. Fix the machine by painting some wires above it. This will create a spiral staircase in the middle of the room. Climb the staircase, and collect the pin from the chest on the balcony.
All other pins can be bought in shops or are obtained as quest rewards. If you've missed any pins other than the two listed above, they can be obtained from the pin trader in Mean Street North.