I have a confession to make. Upon seeing the words "Zombie Carnaval", I assumed it was the cutely misspelled title of an undead carnival sim. I judged a book by its cover, and I was wrong. There's a clear lesson to be learned here, but this probably isn't the correct venue for that. Instead, let's talk about the game itself, and its unique (and zombie-tastic!) take on the endless runner genre.
A group of crows is called a "murder." A group of cats is called a "kindle." And a group of zombies is apparently called a "carnival." Zombie Carnival for iOS is all about running down a street as the leader of a zombie chain and biting humans when they get in your way. You can try pulling the same stunt in real life, but you'll probably get arrested.
In Malcolm Gladwell's book Blink, he proposes that humans actually tend to make up their minds about something within the first two seconds of perceiving it. Everything else is just elaborate justification for those first two seconds: whether or not you got the job in an interview, what colour of car you like, or what sort of pet you're going to get. I don't know if it absolutely holds true for video games, but I did decide that I loved Mobigame's Edge in roughly two seconds. The luminous brilliance of this perfectly realized puzzle game is apparent right from the start.