Making an FPS in blender

For the past few days I’ve been trying to make an FPS in blender. I have some very basic things working so far, but I have some problems that I’m hoping you guys can maybe explain and help me solve.

My first problem is very major. I originally was using the simple motion for my character’s “feet” but due to the poor physics, my player would fall through most objects in the map, so I changed it to servo control. The problem with the servo control is my character slides and takes too long to accelerate.

My second problem is that my bullet doesn’t make contact with the spheres sometimes which does not effect them.

I also have run into problems with the animation of the gun.

When you click to fire fast, you fire without the animation resetting, how could I make it so if you click in rapid succession it would reset the firing animation so it looks more realistic.

I had trouble uploading the blend file so here’s a link

Thanks in advance.