Had a bit of fun playing this. It got a bit easy towards the end, but that might be my fault for investing heavily in long term powers, so my first few games were really hard. I still prefer the more serious theme of The Last Stand, tho.
Took me ages to figure out how to skip through the tutorial... press space to pause once you are actually fighting in the tutorial, then click exit. That's how you get to the training mode, too.