So, I like this. bolter could use a bit more beef to its noise. The bolt rounds do explode so a thump like impact for when the rounds land would do as well. generally everything a space marine does is gonna have impact, so, foot steps and landing from a jump needs to be upped, give it that feel of. "Yes, I am wearing a very heavy suit of power armor." otherwise, this is awesome.
If you can swing it. I can imagine future projects where you go through levels and clear trenches as an imperial guard. it'd be amazing. also. between rounds, ammo and frags should both be refilled.