Here is the full list of all 23 Redie achievements.
Paint the floor!
Spin the revolving door very fast!
Destroy a rocket in flight.
Survive a shot from the Uzi.
Complete all levels.
Complete all masteries.
Unlock all achievements.
Kill two enemies with one knife swing.
Die 1000 times.
Pick up 200 weapons
Kill the last enemy and yourself at the same time.
Perform a quindecuple (15) combo.
Give an enemy your gun, then kill him with your knife.
Kill yourself with a double bounce shot.
Perform a vigintuple (20) combo.
Complete 5 mastery challenges.
Complete 10 mastery challenges.
Complete 15 mastery challenges.
Complete 20 mastery challenges.
Complete 25 mastery challenges.
Complete one mastery challenge.
Perform a headshot with the sniper after a quick 360 degrees turn.
Perform 7 headshots with one revolver.