Ben 10 Omniverse

A really easy way to get this achievement is to load the level called, That Was then.. walk forward and fight the Small electric enemies with young Ben. You can get 5-7 kills and takes no time at all to get 50 kills. Once you have killed all enemies go to the next check point and pick the same level and repeat.

This time you just need to beat 20 more -

Defeat 50 enemies with Ben...now you thing this is smaller than the others, but it is for a reason...Ben is weak, very weak. It take so many more hits than it does to destroy an enemy than using a tranformation. Even worse that the AI like to take a shining to the enemy you are trying to kill making this even harder. This took me untill the 4th level to get without trying. Or if you were just playing as Ben it would not take as long. You can always weaker them first and then transform back to Ben to make it easier.Also could always try destroying the small eltro enemies that you can absorb with Feedback can be quickly killed on Hero mode.