I am going to give Vanlen 1 a shot tonight, honestly I am not sure your style of writing is for me, but I want to give it an honest shot and see if I can get sucked in.
Concerning the feedback and the enemies I think giving them more health might be a mistake. What I meant by feedback is that there should be a stronger reaction when an enemy gets hit, does not have to be fully animated stuff. You could try flashing them with a different color and just moving them back slightly, something that gives a stronger visual indication that your attacks are connecting. Collision-wise just making cool alien girl not be able to pass through enemies or stand on top of them would do a lot, but you would probably have to test it out first.
Your character designs are great btw.