Zombies, Run! app

Options
Some time ago I heard about an app where zombies growl at you if you aren't running fast enough.I'm not sure if it's the same app or not.

Now though, it's turned into a game. I downloaded the 5k trainer version since even though I've been at it for a while, I'm still pretty bad at running (asthma mostly to blame). Each workout is a "mission" and there's a storyline. I think you pick up items along the way too. It incorporates your music (although it only works with winamp and android music 2.3, maybe it does with itunes idk) and occasionally interrupts with a development of the story. It's pretty good, definitely passes the time. You're part of a team of runners that needs to go out for supplies and stuff.

One confusing aspect to me though is I'm not so sure when I'm supposed to be running and not. Like the first workout says 10 min walking, then 1 min walking, 15 sec slow run (ten times), then 10 min free form run. There doesn't seem to be any markers for that unless I'm just confused.

I heard from other people further along that they get so into the story they accidentally yell in the middle of the run.

So I thought I'd share and that maybe other people would enjoy it! It isn't a free app but I think it's on special right now.