In some Angry Birds Space levels, you'll spot a special eggsteroid. If you smash it open with a bird, a wormhole will appear, which takes you - mid-stage - to a special level.
You can always play these levels again by tapping the Eggsteroid planet on the stage select screen.
In our guide, we'll tell you which levels hide golden eggsteroids, show you where the shiny blighters are hiding, and then explain how to beat the bonus level you've just unlocked.
Location: World 1 (Pig Bang) - Level 9
You can see this egg poking out of the grass on Level 9's planet. Simply fire a Blue bird towards it to crack the egg and open the wormhole.
Bonus Level 1: Space Invaders
Use one bomb bird to smash some of the Space Invaders out of the way. Now, wait until the pig in the UFO is hovering above the opening you just made, and fire a bomb bird at the swine.
Location: World 1 (Pig Bang) - Level 20
The egg is buried deep in this grass. Use the Lazer bird's laser-guided attack to smash it open and activate the wormhole.
Bonus Level 2: Super Mario Bros.
Hit the top-most concrete block to make a pig appear. It will then fly off to the right, and land on the floor at the bottom. Wait until it moves left, then hit it with a blue bird.
Location: World 2 (Cold Cuts) - Level 13
The egg is on a planetoid, below the slingshot comet. Fire the Lazer bird backwards, then tap the egg to fire directly into it. This will smash the egg, opening the wormhole.
Bonus Level 3: Breakout
Use your Red and Blue birds to smash away at the central pillar, to make the middle pig drop and pop. Then use Lazer bird to target the top-left, moustachioed pig.
Location: World 2 (Cold Cuts) - Level 25
This egg is on the same planetoid as the slingshot. To reach it, fire a Lazer bird diagonally down-and-right, then use its laser-guided attack to swing back and smash open the egg. This will activate the wormhole.
Bonus Level 4: Bubble Bobble.
A pretty simple stage. Just use your three birds to smash away at the ice and defeat the pigs.
Location: World 2 (Cold Cuts) - Level 28
This one is a little more hidden than its predecessors. It's buried under snow, on the far left of the ice planet. Attack it with any bird to open the egg, and activate the wormhole.
Bonus Level 5: Star
Use a Lazer bird to smash your way into the centre of the star. This will cause the structure to collapse in on itself, popping all the pigs along with it. Pick off any un-popped pigs with your leftover Lazer birds.
Location: World 3 (Fry Me to the Moon) - Level 10
This eggsteroid is hiding in the grass behind the birds's catapult. To collect it, simply fire the purple bird towards the left of the screen, and use its laser-guided kamikaze dive to charge at the egg. If you miss, restart the level and try again.
Bonus Level 6: Pong
This Pong-themed level has a pig bouncing back and forth between a pair of paddles. Fire your red bird just ahead of the pig's trajectory to score a hit, but watch out for the moving concrete paddles.
Location: World 4 (Utopia) - Level 16
This egg is hiding in the undergrowth, directly below the catapult platform. It's easy to grab: just fire the purple bird down, and then use its laser targeting skill to fly back up and into the egg.
Bonus Level 7: Orange Bird
This bonus level celebrates the Orange bird's cosmic debut, as it resembles the scrawny bird's inflated alter ego. Hit the pigs closest to the planet to cause the other pigs to succumb to gravity and pop.
Location: World 4 (Utopia) - Level 24
This egg is hiding high above the pig's fortress. You may need to zoom out (by making a reverse pinching gesture with your fingers) to see it. Now use the purple bird's kamikaze attack to grab the egg.
Bonus Level 8: Tetris
In this Tetris-inspired level, you need to push the blocks to make them fly off and hit the pigs. An easy bonus level, we reckon.
Location: World 6 (Pig Dipper) - Level 24
An easy one to grab, this time. It's sat on the planet at the bottom of the level, ripe for the picking. Simply waste your first two birds, then use the purple bird to make a laser-guided dive bomb towards the eggsteroid.
Bonus Level 9: Pac-Man
This bonus level is inspired by '80s dot gobbler Pac-Man. Use the springy jelly pads to propel yourself into the ghost-like pigs, and wipe them out.
Location: World 7 (Cosmic Crystals) - Level 11
Smash the bottom crystal planetoid with a pair of red birds, so there's no longer a gravity well at the bottom of the screen. Then, fire your purple bird into the gravitational well of the main planet so it swoops around and near the egg. Finally, tap the egg to zero in and smash it to pieces.
Bonus Level 10: Pinball
Use the bouncy pads to clear this pinball-inspired bonus stage.
Rover 1 (Viking Lander)
Location: World 5 (Red Planet) - Level 3
In the "Red Planet" levels, Golden Eggsteroids are replaced by real-world rovers launched by the space boffins at NASA. The first once you'll meet is 1975's Viking 1 Lander.
To grab it, fire a purple bird off backwards into gravity well. It will disappear off the bottom of the screen, but when it comes back up in the right-hand side, tap on Viking to crash into it.
Bonus Level R1
Use the top-most steam vent to attack the structure at the bottom, and the bottom vent to storm the fortress at the top. An easy one, once you've figured out this particular quirk.
Rover 2 (Sojourner)
Location: World 5 (Red Planet) - Level 4
Next up, it's tiny 1997 rover Sojourner. Fire a purple bird into the vast expanses of space below the level, and then tap on the ickle robot to make a laser-guided strike.
Bonus Level R2
Use your orange birds to shunt the rocks and wooden boards into the gravity well above, and the steam vent on the right. Use the other birds to pick off any unlucky survivors.
Rover 3 (Opportunity)
Location: World 5 (Red Planet) - Level 18
In 2004, Opportunity landed on red soil. It has since gone on to live for eight years, dutifully looking at rocks and snapping lovely panoramas of Mars. And now you can crush it with a bird.
Launch any of your birds into its brittle frame to smash it to bits. Congrats - you just wrecked a $400 million robot. I hope you're happy.
Bonus Level R3
An easy level. Lob some birds at the explosive lava rocks at the back to do untold damage, and then pick off the leftovers with well-placed shots.
Rover 4 (Phoenix)
Location: World 5 (Red Planet) - Level 28
In 2008, NASA's Phoenix lander set down on Martian soil. Now, you get to smash it to pieces in order to open up a bonus level. Science! This one's easy - just fire a bird into the steam vent coming out of the planet in the top left-hand corner.
Bonus Level R4
A rather easy level to beat. Focus on the rocks that are hidden behind ice. Smash those to let the rocks loose, and cause massive destruction to the pigs below. Then, it's simply a case of using the remaining birds to pick off the last few pigs.
The chapter Beak Impact added some secret NASA Spacecraft for you to find. Break these ancient interplanetary travellers with a bird to unlock a secret level. Here's how to find each craft.
Spacecraft 1 (Deep Impact)
Location: World 8 (Beak Impact) - Level 8
This craft is hanging around at the back of the level. Use purple bird's pinpoint targeting to fly straight to Deep Impact.
Spacecraft 2 (Dawn)
Location: World 8 (Beak Impact) - Level 11
This one's easy. Just zoom out and fire a red bird up to smash the spaceship.
Spacecraft 3 (Orion)
Location: World 8 (Beak Impact) - Level 17
This one's so high up, it's off the top of the screen. Never mind - the lack of gravity means red bird will keep flying up until you hit Orion.
Spacecraft 4 (Osiris Rex)
Location: World 8 (Beak Impact) - Level 25
This spaceship is also up very high. Use the purple bird to smash it into tiny space pieces.
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