Apparently, when I put a bunch of stuff in my storage and it said it was full it just kept eating items as I clicked, but they are now nowhere to be seen.. this includes all the skillbooks I've been saving. bah..
SHIT CANT BE RANDOM IN RUNNER GAMES, unless you actually think about how to do it. Which you obviously didn't. And whats with the annoying movement and messed up collision detection with the balls in London. 1/5 for poor effort.
Lightning, Duck and BFG is unstoppable. Just use the BFG as a shield as you go across the map while spamming the other two. On maps where you can't hit fast enemies and the last boss, just use the Laser Lock. Also, if you want to take down heavy enemies, go on top of them and use lightning. Especially effective on the last boss.
I killed the end without him even getting in turret range. :) Just get 9999 mana, let your enemy push to your tower, then start spamming dragons and angels while you push them back. Then, when you reach the tower start spamming hobbits and don't stop until it's over.
Another trick is when he's at a good range you can make your arrows fall straight on his head so your special arrows hit like 30 times each and he also gets hit by the explosions. Spamming mages might help too, I did but I don't know if it helped or not.