Level 11: Package

This is another collection hiding in plain sight. As you progress through the level, be sure to grab this white box (above, top center) from the porch of your human apartment building. If you snatch it for an unsuspecting owner, it’s not porch piracy.
Level 13: Anemometer

From the start of the level, jump from the garbage truck to the first biker you see. When they stop on the sidewalk, jump into the shadow of a nearby freight truck and wait for a car in the opposite direction to pass. Hitchhike in its shadow until you see a car parked on the side of the road with a large sign. this anemometer Just behind that sign (pictured above).
Taking this collectible will also reactivate the nearby windmill. If you touch its fan, you’ll be flung across the street just as you came, into the shadow of the car behind the cargo truck, and can continue the level as normal.
Level 14: Lost Package

Initially, ride the forklift inside the warehouse to reach the first of several conveyor belts. Use the springs to launch yourself onto the conveyor belt and ride on the shadows of passing packages. Just in front of the fork of the conveyor belt, jump off the fork and into the jumble of crates. You can see the misplaced package from here (above, top right), but you can’t reach it yet.

From here, jump to the nearby container and use the spring next to it to launch yourself onto the parked forklift. When you are in the forklift’s shadow, press the interact button to raise the forklift, which also expands its shadow. Not only is this a useful tip to remember for the rest of the stage, but it gives you plenty of room to reach the misplaced package. You can use the nearby spring to return to the pile of crates and continue the level.
Level 14: Wrench

Continue through the level until you reach the crate transport tunnel. At its far end, you’ll find a worker testing a robotic arm. Instead of jumping into the worker’s shadow, go a little further past the last obstacle and into the storage area.

At the end of the driveway, jump into the shadow of the man on the left. From here, you can jump from the nearby springboard onto the forklift and then onto the container. The wrench is at the end of the channel behind the second container (bottom left in the photo above).
Level 14: Crate

At the end of the stage, you end up in a crowded storage area, where you have to navigate between tall shelves using the shadows of passing workers or forklifts as stepping stones. You can usually exit this area by jumping into a pipe and letting it take you to the end of the level (above).

However, if you jump against the flow of the pipe long enough, you can carry it to a very hidden area where you can find a stray crate that has fallen off a shelf (above).
Level 16: Chair

At the end of the stage, before you jump into the dog’s shadow, back off a bit and visit the nearby restaurant’s outdoor seating. Cushions and chairs are located in the shadows of the side of the building. It’s easy to get it as long as you don’t leave before you get it.
Level 17: Screwdriver

From the starting point, jump from shadow to shadow along the nearby canal until you see this collectible next to a tree. The screwdriver (above, left of center) is the same color as the inexplicable highlight in the level’s color scheme, making it difficult to spot.
Level 18: Cane

The stage is set on four separate “islands” of the city’s canal system. You start with the first one. If you jump from tree to tree along the edge of the current island, you’ll find abandoned walking sticks in the shadows of park benches (above right).
Level 18: Schoolbag

Ride the jogger shadow to the second island and get off at the playground. You may need to adjust your camera to see it, but the bag is clearly visible near the jungle gym.
Level 18: Trash Can

You may discover this yourself. The third collectible at level 18 is found in the duck pond on the third island (above, bottom center). It’s easy to jump from the shore.
Level 18: Bicycle

If you grabbed the previous collectible, you may find this collectible by mistake when you try to leave the duck pond. Just a few yards away from the trash can, in the same pond.
This is most likely because the duck stole the human’s bike in level 5.
Level 19: Plastic Trash Can

From the starting point, jump to the right a few times to the parking meter, then a large jump to the lamppost across the street. This is the hardest part; now you can grab the nearby plastic trash can on the side (above, center).
Level 19: Barrel

Starting from the last schim, proceed through the level normally until you see the missing schim hovering in the shadow of the parked car. Use the shadow cast by the two people next to that car to reach the wood chips, then grab the bucket from under the nearby patio table (above, off-center).
Level 19: Bicycle Pump

As you cross the main path of the level, you’ll pass near a bridge with a lot of people on it. Cross the bridge to its far end, then orient the camera so the bridge points to the upper left corner of the screen, as shown above.

There’s a collectible in every direction here. If you turn right from here you should find the bike pump (above) under the shade of a tree at the end of the driveway. It’s thin enough that it’s hard to see.
Level 19: Barrier

From the previous collectible, go back to the bridge and take the other path. There’s a row of traffic barriers here, and you can pick up the one that got knocked down in the middle.
Level 20: T-shirt

At the start of the level, jump into the shadow of the first passing car and let it take you all the way to the small bridge. Before raising the guardrail, jump into the shadow of the nearby streetlight and onto the parked van.
From the van, make your way to the other side of the nearby fence. It’s tricky, but there’s enough little shade here to reach the clothesline on the far side, and from there around to the backyard of the house. The T-shirt is located behind a nearby fence (above).