Plus, I'm number 5 on the online leaderboard!
For $5, it's pretty fun if you like Oregon Trail. Plays a lot like it, and there doesn't seem to be any "instant death" events. At least I hadn't encountered any on normal difficulty. For example, I've failed "fording" a few times (in this game, it's breaking through a horde of zombies) and it wasn't instant lose.
First time I've ever gotten on an online leaderboard for anything: I'm number #4 campaign mode. Probably would be #1, but someone has figured out a way to either farm or exploit the point system for spots 1, 2, and 3. And was #5 on endless mode, currently bumped down to #8; but it looks like someone figured out how to exploit or farm points in that mode, too.
Oregon Trail: Zombie Edition! Seriously, though, that looks badass. Also, you can give it a try for free on facebook, if you're unsure whether you want to buy it for your phone.