I love it when I don't have enough mana to summon my Eli Manning Hobbits and I have to fight off the enemy by myself with just my arrows and I have a perfect feed on the first guy and then my bow decides to move itself to shoot straight down
One way to get the x30 combo is on Vault Defense Level 9 - on the wave with all the spiders just wait until most on them are on screen then use a nuke or bomb...I got x38 on my first shot!
I'd suggest that the free play at the end should be in same as in game but with all tools and colors available, it would be fun to see what all is possible...then maybe some kind of gallery to show of everyone's creations...otherwise awesome game!