On buying anything, imperials and ounces, there should at least be a sort of 'Are you sure?' kind of button, just in case you didn't intend to spend 10k imps on a standard booster or 15 on a pro booster.
I feel, there should be a little competition here other than clan wars. Maybe you could add a tournament option where people pay imperials to get in. Maybe like a tyrant function where you don't use the cards you get but boosters you buy as the pay in price. It levels the playing field to the higher leveled people.
I don't like how synapticon made a mission that is easy and only gives 3 event points. Some people can't beat the other mission, and some guys just can't do the tournaments. I think he should've at least made that mission 5 or 10.
I notice, that this game doesn't seem to have a whole lot of counter in it. In card games, I've always liked the mechanics that counter the most powerful. Maybe like one here something that stops battle cry instead of needing a guy with guardian maybe a terrain with guardian. This comment will probably be voted down but I'll make it anyways.
People say you can communicate through F1-F6. I listed them here for use. + so you can see it more often, or just write it down when you get the chance. Hope it helps!
F1- Need Backup
F2- Regroup
F3- Barricade Down
F4- Move out
F5- Deploy here
F6- Spawn point
Killing a lot of zombies, and only getting a few, say like 300 + rewards 20, it HAS happened, it's probably because someone in your squad has a laggy weapon (say the flamethrower), your connection is bad, or something else that is a huge internet hog is being used currently. Either or, it's something with either your squad, or your internet.
I think they should make forest have a bit more "might". I mean, I've seen forests with great support and crap, but unless you have a Dreven, or Earlinde, you kind of succeed to terror. Plus, there are a LOT of evil, twisted sides of forest that I'd like to see with it. Stuff that doesn't look likea monster but deadly, like the poison dart frog, or the Venus Fly Trap.
There needs to some close combat weapon like a chainsaw or something that uses the same kind of ammo usage as the flamethrower. Like in everything you see about killing zombies, there is a chainsaw.
 "Berserk: The Cataclysm")
 "Tyrant")
 "SAS: Zombie Assault 3"){kind=icon}
For now you can compete in already existed tournaments - King of the Hill and Treasure of the Dragon.