Very Well Done
This is a very well done flash game. The idea of a mario defence game was great by itself, but with your variety of towers, and the great back story made it even better. At the first few levels I thought "he has a good idea, but this looks to easy to just put up spring towers and advance them" but After a bit of playing I found that this was really good!
Some of the towers were pretty useless like the hammer bros, but I won't take away points for that. My favorite was the wiggler tower. I loved analyzing each stage and finding which tower would be good where. It was fascinating on the work you put into the intro and other features.
The loading time was worth every second. Sand box mode was very fun, but at times lagged. I noticed in the "scores" section there were some hackers who got 2147483647 score, so you might want to tighten your security. You could also add more variety to the enemies like super star luigi or mini mario, etc. Luigi looked very difffrent then he usually does. I would suggest using super star Saga sprites instead.
In conlusion this was a very well done game, and I gave you +5 for the idea, +3 for the towers -1 for the variety, +2 for the backstory, -3 for the lag, +2 for all the features, +2 for all the levels, and +1 because of all the trophies. -1 because I'm evil. Deserves by 10/10. Thanks for reading my long review!