I'm pretty sure the developer of 'I Am Vegend- Zombiegeddon' thought to himself "If I just mash-up all the popular casual games, my game will be the best casual game out there".
Unless you never watch movies, you have noticed the title of this game is ripped from the movies: I Am Legend + Armageddon. Another thing the developer thought would be clever but in my opinion it is unfunny and just dumb.
Like I said before, the game basically ripped everything from other games with in particular "Plants vs. Zombies" and a little bit of Angry Bird and Worms.
Your goal in the game is to defend your 'seeds' from attacking enemies. Everytime you have to click on one of your plants and click somewhere in the screen to shoot/attack. After missions you can buy new upgrades etc. that sort of thing.
To be honest, the game is not that bad. The graphics are OK, the gameplay (although a little buggy) works OK and I might have recommended it if it did not rip everything from other games.