In all 30 levels of the game, there is a hidden gaming console to be found and delivered.
Couple things to note from my play through:
-They are counted for your achievement progress only when the level ends successfully with the gaming console inside of your moving truck.
-There doesn't seem to be a way to check which ones you have. Consoles you already have still appear when replaying levels. Be careful to making sure you get them all. On my play through I had restarted a level before finishing and counting it, and had to replay half the game to figure out which level's console I was missing.
-You don't have to worry about finding any on arcade or memory levels.
-Playing with assist mode on and having items in your truck be removed is helpful. The console will not be removed. Always easy to see if it is in your truck.
For those who prefer a written guide to these, here you go:
Level 1 - Holly's Home
The first console of the game is found on the far left side of the map, on the front left of your moving truck. Go ahead and pick it up and drop it in your truck and finish the level.
Level 2 - Pepperoni Palace
In the backyard, you will see a picnic table with a radio on top. Underneath this table (Move or flip the table) is the next hidden console
Level 3 - The Hoop House
Once again head to the backyard. On the pinkish hammock, will be your next hidden console.
Level 4 -Poolside Pad
Head to the kitchen on the right side of the house. On the south wall, left side, the console is sitting on the counter top. Can be easy to miss this one.
Level 5 - Jerry's Apartment
Move on into the house and head to the northern most room of the house, the bathroom. In the corner closest the camera, near the green bathtub is your console. Can't see this one so just hold your trigger and walk into the corner.
Level 6 - Case de Cliff
Head up to the right side of the house, into the room with the red car. Move towards the car and it will fall out of the window. (Great reference) In the back right of the room will be your console, right in front of where the car was.
Level 7 - Summer Chalet
Once you are inside the house, head to the bedroom on the south side of the house overlooking your truck. In the corner closest to your truck, the console is on the floor out of camera view.
Level 8 - 21 Slick Street
Don't even need to go into the house yet for this one. Move to the left side of the house, where the red car is. On the car's left side is the hidden console.
Level 9 - Snottsberry Farm
This one is on the Northern corner of the map. Head into the northern most pen and head up the ramp. There are some hay bales up here, go ahead and move them to reveal the hidden console.
Level 10 - Packmore River
Here is the Frogger level. Scoot across the road, and before the river on the left side the console awaits.
Level 11 - The AAAAAH-tari Office
On the upper level, head to the corner closest to the camera. In the little hallway behind the trolley, the console is on the floor.
Level 12 - Dread Manor
This one is upstairs, in the western most room. The rooms is the one with the evil piano. The hidden console is in the bottom left corner of the room.
Level 13 - Roundabout Mansion
Go through the door southwestish from the main fountain, into the art room. Looks like a giant dinosaur bone or something, idk. Anyways, in the bottom corner of the room, out of view is the console behind some sculpture. Be careful not to knock the sculpture over if you are going for the bonus objective.
Level 14 - Obadiah's Orchard
This console is sneakily hidden behind your truck, under some hay bales. Move them to reveal it.
Level 15 - Lenny's Mansion
Another outdoors one. Head to the front entrance and follow the wall into the corner of the house in the forest area. It is beneath a tree here.
Level 16 - Neighborhood Watch HQ
Inside the back garage with all the fans, there is a giant giraffe stuffed animal on the floor. It is behind this.
Level 17 - Deserted Depot
In the middle room on the right (the one with the big vending machine), behind the yellow couch hides the hidden console.
Level 18 - Sealed Storehouse
This one is in the western most room. This room has a desk and a water cooler. In the corner closest to the camera hides the hidden console.
Level 19 - Locked Lever Lab
At the top of the map is a small upstairs area. Head the room at the end of this area, and behind the desk in the corner is your hidden console.
Level 20 - Flamethrower Factory
In the room with the flamethrower lever, near the spawn. Its in the southern corner closest to the camera.
Level 21 - The Chase
Well hidden one. A few train cars in after the room with two levers, pizza boxes and the gnome for the bonus objective. The one you want to be at is where you move the yellow couch. Look at the road, and you should see a green truck that has the hidden console on top of it. Jump over and grab it.
Level 22 - The Floor is Guava
Once the level expands, head to the right. Here is the path with the changing colorful floors. Cross this path to the area with the items. The hidden console is in the corner closest to the camera.
Level 23 - Stairway to Melon
A not so hidden, hidden console. Right at the start you can see it, on a floating platform in front of you. Head left and use the moving Hogwarts staircase over to it.
Level 24 - Guava Run
This one is hidden well behind your truck. Walk around and hold LT and you will pick it up as you walk behind it.
Level 25 - Satellite Base Alpha
On the left most puzzle room, the area with the yellow floor. On the south side of this room is the green tube you need, and right before it a small wall. The console is in front of this wall, out of view.
Level 26 - Revolution Station
This one is also out of camera view. It is in the Southern most corner of the main room with all the colorful circles that spin the walls. It is in the corner next to the pink circle.
Level 27 - Guavatron
Head through the spinning thing to the west side of the area. At the back of this area you wil see an area with couches and the TV. Behind this television on the cliff side is the hidden console.
Level 28 - Contraband Cluster
Head southwest from the truck, across the western most fan to the next island. On the right side of this island you will see some greyish brick walls. The console is hidden behind the right section of the brick wall.
Level 29 - Pack Rat Planet
This one was kind of tricky. Easy to see though. It to the left of the truck, on top of a toilet on the face of the cliff. I wasn't able to quite reach it, so I jumped down on top of the toilet, moved over a bit so I could pick it up, and threw it to safety before I died. When I re spawned I went and picked it up where it landed.
Level 30 - The Final Move
The final one! This is a boss level, and the fight takes place in different stages. Every time you deliver an item the attacks change or speed up. After 4-5 items, the boss will drop big objects all over the grassy area. The console will also fall in the front center of the area.
That is all of them! If you are having any issues finding any, or have a way to make a description more clear please let me know.