For this achievement all you need to do is play through and complete the first of 3 episodes on the good side. The first episode consists of 5 levels all of which shouldn't really be a struggle and you should manage to get through them whilst just playing through and enjoying the game. If you are that way inclined you can use cheats which do not disable the achievements. They are:
Stud Magnet: LK2DY4
Always Score Multiply: 9LRGNB
Extra Hearts: ML3KHP
Invincibility: WYD5CP
Minikit Detector: ZXGH9J
Score x10 Multiplier: 18HW07