Thanks so much!
You are on the level where the game introduces the first enemy type(level 3) or the second enemy type(level 5 I think)?
A lot of people have a hard time understanding the levels 3 and 4, and I can't say it's their fault. We didn't really explain that you can use cards to reflect projectiles by changing direction, nor that enemies can deal friendly damage and self-damage.
We even had to give a hint on the game's page. But that's not a good solution and makes me realize that it is of the big flaws of the game.
Thanks so much for both the thought-provoking criticism and positive feedback!