Wow! Is that Plants vs. Zombies II ?
Indeed, this is one of the best TD-Games I've seen. You have a couple of tower strategies that only fit some enemy properties, and I like keeping players very busy during waves, e.g. by collecting money. Moreover, some ideas - most of them already mentioned in previous comments:
1. The language of the intro is quite poor - please revise that (sorry, my English is poor as well, but this is just a comment)
2. Increase the screen, enlarge the images, everything is very, very small in this game.
3. Make updates visible. As you keep us busy collecting money, we don't have the time to click on every plant to see what level it is.
4. Planting crops is a prosperous job during the game, if you plant them early enough, it will make you rich and mighty - extremely mighty, as you soon can afford almost everything. As 'Simbrian' suggested: what about "having the price for those crops increase each time you buy one"?
5. And what about having the characters introduced during the game instead of showing them all in the beginning? Maybe you could add some new plants and monsters during gameplay and show them bit by bit after a wave is over? This could improve excitement and fun.
However, if you don't change anything and let the game just as it is, this is still a great job. Thank you for this game.