Easy "Couch party" achievement...
	Various Steam Achievements...

A total of four controllers are required (or on a PC, three controllers in addition to the mouse and keyboard). Start soloing any tomb, except for the small challenge tombs. Before reaching the end of the tomb, open the menu and change the game type to a 4-player local game, then select "Continue". This will allow the other controllers to choose a character to load at the last checkpoint. Get at least one character to the end, allowing the others to die if desired. Note: You may need to control two characters at a time to end some levels.

Complete the indicated task to unlock the achievement.

Achievement	How to unlock
A journey begins	Escape the Pyramid of Osiris.
All bark and...	Complete all Set challenges.
Bad...Doggy?	Defeat Set.
Bling me up!	Wear two rings and an amulet.
Burn it with fire!	Complete the Tomb of the Lamplighter.
Couch party	Finish a tomb in a 4-player local multiplayer game.
Didn't see that coming	Defeat the Oracle of Osiris.
Gotta have them all	Complete any red skull challenge.
Gotta start somewhere	Find your first weapon.
Heartburn	Complete all Sobek challenges.
Hey, at least you are the best at something!	Have the most deaths in a tomb in a local or online multiplayer game.
Human cannonball	Bomb a player in a Magic Shield in a local or online multiplayer game.
I love tombs!	Complete all Challenge Tombs.
I should buy a boat	Complete the Tomb of the Ferryman.
I was told there would be boats	Complete all Tomb of the Ferryman challenges.
Into the future	Complete all Tomb of the Timekeeper challenges.
Learn from the best	Complete any gold score challenge.
Lit all the things!	Complete all Tomb of the Lamplighter challenges.
Long distance relationship	Finish any tomb in online multiplayer.
No bug is too big for these boots!	Defeat Khepri.
No worries, I got this!	In a 4-player local or online multiplayer game, be the only player to not die in a tomb.
Not on my watch!	Revive another player in a local or online multiplayer game.
Nothing a belly rub can't fix	Defeat Sobek.
Oh, were we supposed to share these?	Get the most gems in a tomb in a local or online multiplayer game.
Primus Inter Pares	Get the most kills in a tomb in a local or online multiplayer game.
Pyramid scheme	Complete all Pyramid of Osiris challenges.
Snake charmer	Complete all Tomb of the Silversmith challenges.
Stick'em with the pointy end!	Complete the Tomb of the Torturer.
That's a wrap	Defeat the Pharaoh.
The stabbiest tomb of all	Complete all Tomb of the Torturer challenges.
Time is of the essence	Complete any level time challenge.
Time keeps on ticking, ticking, ticking	Complete the Tomb of the Timekeeper.
Tomb Raider	Complete all challenges.
Up for a challenge	Complete a Challenge Tomb.
What were we standing on?	Complete all Khepri challenges.
What's in the box?	Unlock a treasure chest.
Who builds their own tomb?	Complete all Tomb of the Architect challenges.
Why's it have to be snakes?	Complete the Tomb of the Silversmith.
You know what grinds my gears?	Complete the Tomb of the Architect.
Your death won't be in vain!	Collect enough canopic jars to unlock an onyx weapon.