there r some advices and skills playing this game summaried below (hope it?s helpful):
In Adventure Mode you won?t get much breads as in PvZ, so you should take good use of magic (e.g. lighting) to protect cookers.
It?s not easy to pass every level for only one time. Personally I don?t recommend go IAP. To understand every role in this game is the key to clear all the levels with high scores.
For the racket soldier, maybe there?s not enough archers to fight against them at the beginning. You can put a cooker (or something cheap) in front of racket soldier so they exploded together.