It's very neat! It does get a little easy to predict though, because it very often comes down to raw speed, since units can only dodge a bullet by running in a straight line away from it - Either they're fast enough and they get away, or they're not and don't. I've seen a fair bit of draws where a pair of survivors just endlessly dances at each other, unless they happen to be close to a wall :D
But hey, simplicity is a major point here. Maybe I'm just overthinking it. Good stuff!