Why won't my invaders move left?

I researched several space invader demos before I started my little game. Thought I had it, but apparently I'm missing something. I've gone over most of the demos again trying to find what I forgot, but I just can't figure out why my invaders won't go left. I don't want the invaders to shift down, just go right and left.

I would post the c3p, but I'm using a paid star plugin and the project won't open unless you have the plugin. Hopefully the images of the code will do.

Any ideas?

(Note: I've edited the code so much trying to figure this out, I may have stuff I don't need, but don't realize.)

invaderjumpsize starts off equal to 10. But it never changes, so they only move to the right. You would have to set it to -10 somewhere if you wanted them to move left.