crobemeister

With time you will recognize how the enterable building look, there are only a few variations. And yes even though a zombie is not aggroed it will naturally gravitate toward your general area. This is a mechanic in the game not a glitch. It doesn't mean they see you, so just lay still till it passes. Also about the running, when you stopped were you going up hill? You cant run directly up hill, you have to side strafe left or right while looking up hill. I like to toggle walk/run to walk by default and hold shift to run. i spend more time sneaking anyway, so no need to have it toggled to run.

I dont thing you know what iron sights are... Go to first person, tap the right mouse button to bring up iron sights.