Just did the hard badge with rear BIG wheel front normal wheel and using remote/trex...try to punch those walls with the trex instead of the spike...keep them for the end and it all should go well! Good luck ALL!!
** LEVEL 17 WALKTHROUGH **
-Have only 1 enemy remaining, shooting bullet with no jet-pack
-Have many perks (if not all of them) (you'll need a LOT of Mana-focus)
-Have all the perks related to NEO & the dashing-stun perk
-Then all you have to do is freeze time and dash the enemy everytime the bullet is halfway then you get back in place while the enemy is stunned
-With enough mana you should be able to do it without removing the freeze-time (F)
-I did it while being at level 55 with around 450 mana
-Good luck and get that badge!