You can do this with one playthrough of the first level by doing a glitch.
Right when you get to the tree you have to collapse to beat the level, kill every minion and spikey guy except keep one that you will stay on. Now press B to get off, then press it again right after to get back on. When you do this the third time, another spikey guy will appear and you can jack him and ditch the other guy. Then just rinse and repeat.
By doing this simple glitch you can get the spikey guy skin AND the 30 gamerscore achievement without having to play levels over and over again.