There is no guide for this game yet. But apparently it is EASY POINTS! 

Go for the Gold - 15 points

Win a gold metal on a challenge map.

Out of the Blue - 25 points

Once you have control of both portals, only enter the orange portal.

Rat's Tale - 15 points

Find all the Rat Man dens.

Is Anyone There? - 20 points

Complete the game without ever taking a bullet.

Saw That One Coming - 5 points

Cause a rocket sentry to destroy its own rocket when the rocket has been redirected back towards it.

The Camera Adds 10 Pounds - 10 points

Knock a turret over with a security camera.

Like a Rat - 20 points

Trap yourself in a test chamber so that GLaDOS has to help you continue.

A Feeling Like Floating - 5 points

Dissolve a turret.

Tests Like Chicken - 15 points

Find the chicken's test results.

Cupcake - 10 points

Beat 5 advanced chambers

Fruitcake - 25 points

Beat 10 advanced chambers

Vanilla Crazy Cake - 35 points

Beat all advanced chambers