This is a simple enough game to figure out, but if you just want to speed through it - and more importantly, know where to make the save backup so you don't have to play it twice for the platinum - read on.
If you'd rather follow a video, check out BlakkVulture's HERE.
Office
Walk forward to the Exit door and open it with Square
Follow the hallway around and enter the door at the end
Go down all the flights of stairs (it's really dark but the red doors will help you orientate yourself) to the bottom
Open power box and pull switch - I'm Not Even Supposed to Be Here 
unlocked
Go all the way back upstairs to 4F and enter the hallway
Jungle
Walk forward onto the bridge until you reach an intersection
Keep walking forward off of the bridge and onto the dirt path – Is This A Dream? 
unlocked
Back up to the intersection on the bridge and take the other path
Keep walking into a stone area until you start a third-person view segment
Third-Person Segment
Just keep heading right, platforming and/or climbing as needed, until you can enter a door with white light
Go down all the stairs and enter either door (x2)
Walk right through the house until a series of cutscenes plays
Follow the on-screen prompts, pressing R1 and L1, until you can walk into the spinning thing
Kitchen
Just keep walking right, pressing L1/R1 as needed to navigate around things in your path.
When you reach the end, you will unlock I Was Free I Was New .
Bedroom Puzzle
Pick up the three symbols. Two are in plain sight and the third is underneath the balcony – walk through the door and use L1/R1 to turn the room – I Could Be Me I Could Be You unlocked
Winter
Walk left until you reach an intersection
Take the intersection and follow the path
Walk all the way around the wheel – you should hear a tone and her lantern should get brighter. If it does not, do another loop around the wheel
Go back down to the intersection and walk left to another intersection
Go up this new intersection and walk all the way around the spinning pedals – again, there should be a brighter lantern and a sound. Repeat if not.
Go back down to the intersection and walk left to another intersection
Follow the intersection up – walk around the lantern – it will be obvious when you've succeeded
Go back down to the path and keep walking left – I Was Just Having Fun unlocked
Keep walking left past the bicycle
Winter Puzzle
Pick up the three symbols.
For the tallest one, hang on to the bottom part of the ladder and rotate the puzzle around (L1/R1) until the other half of the ladder lines up and you can climb up to it
For the one on the platform, climb up the bottom part of the ladder and stand on the floor in the middle of the house thing. Rotate the puzzle around until the floor makes a bridge over to the platform -Bentley, What Have We Done? unlocked
Bunny Rabbit
The controls for this part are terrible – I had the most luck here by just pushing the directional sticks halfway instead of fully. The bunny goes slower this way, but is easier to control and seemed less likely to “spook” and run to the side of the stage.
When the area opens up, just keep going forward, following the path around and down a small hill
You will eventually see a large flat gray rock/ramp on your right
Jump on that rock and walk to the top of it.
Turn right and jump onto that rock – I'm pretty sure you can't make the jump to the rock directly in front of the gray one
Carefully go up this new rock, jump to another one, and follow this rock ridge up and around to the left, back towards the entrance to the stage
Eventually you will see a rock jutting off to the right, that will allow you to jump across the grass and to the other side. Do so.
Jump into the water and swim forward between the rocks
Once past the rocks you should see a small bit of land on the left you can use to get out of the water
Go up the hill and left and face the water
Make a long jump onto the rocks in the water and cross all the rocks and into the grass on the opposite end of the water
Go forward towards the rock archway – You Are So Important To Me unlocked
Keep going forward under the rock archway until you reach the fence
At the fence, turn right and head down to the water
Swim across the water and push forward until you see a steep hill on the right
Go down the hill
Spring Puzzle
Again, pick up the three symbols. Get on the half-bridge and rotate the stage so you can pick up the first symbol. Go down the ladder and stand in front of the wall with the ladder on it. Rotating the stage will open the wall, allowing you to access the second symbol. Finally, climb up that ladder on the wall and stand in the little stone area it leads to and rotate the stage to move the platform around so you can get the third symbol – I Can't Ever Lose You unlocked
Toy Car
Follow the path – there's only one route you can take. Through the house and through the woods. If you want to shave off some time, try missing one of the ramp jumps in the woods and falling down a few levels into the water.
Eventually you will end up on a beach. Collect or ignore the symbols; just start heading right and you will eventually ramp off of a dock into the water – That's A Feeling I've Forgotten unlocked
Summer Puzzle
Press start/options, and quit the game.
BACK UP YOUR SAVE.
Load the game back up. If it just says “New Game,” hang out on the title screen for a bit and it should eventually allow you the option to “Continue”. You may even have to press “continue” several times in quick succession for the game to load again. And if you try to make this save backup later in the game, it just starts the entire game over. Yes, really.
This one's easier, as there's less stuff to keep track of. Rotate the stage so you can move across the docks and lower the platform with the birds on it. Rotate the stage to raise the platform and step onto the one with the honeycomb on it, then rotate again to get back on the bird platform, now at level with the top of the lighthouse. Rotate the stage around until the platform on the side of the lighthouse drops and you can walk across. The only tricky thing is timing your walk on the two platforms that just swing around on their own on the line leading to the crow's nest – I Used to Not Worry About Any of This unlocked
Halloween
Walk right, collecting or ignoring the symbols, until you go under a ladder
Keep going right, avoiding the enemies
Eventually you will run into a massive jack o lantern
Start going left until you reach the zombie platforms
Turn around and start going right again and the stage will end – Superstitious or Ambitious unlocked
Fall Puzzle
This one is pretty easy to figure out – to get to two of the symbols, walk into the mine and walk all the way to the right onto a hidden elevator, then rotate the stage to be brought up to the mine cart – Everyday Felt Like Halloween unlocked
Epilogue
Cutscenes
Choose “Yes” - How May I Help You? unlocked
Close out of the game, reload your backed up save, and play through Summer Puzzle, Halloween, and Fall Puzzle again
This time, choose “No” - There's The Whole World Out There and There's Also A World Inside Of Me 
unlocked
