It's a nice game, but like all other games that share this concept, it gets boring fast. Defense mode just becomes a matter of who has the most time on their hand, and we can clearly see that the top 50 really need to find another way to spend their time
survival mode actually relies on skill and thought on what combination of purchased items could best be used to help you survive an endless round. I applaude this
As many have alraedy stated, defense mode needs more spice. How about something like a boss every day that has huge attack power that would actually make it worthwhile to try and upgrade your base's health to 50,000
 "The Endless Zombie Rampage"){kind=icon}