Hi!
Nice lowpoly axe. Clean shape. But too havy for a game model --> 36 Mb! (Jesus!! :D )
Screw should be merged with the axe. In best case scenario created with texture (baked from High poly mesh to lowpoly to get normal map). Polycount for such small object is too high:
Blade topology is ok but for handle again too much edges. As you can see, only 12 edges is completely enough using "Shade smooth" option:
Good luck! :)