It is a really interesting mechanic, to have the weapons attach in a specific way, kinda fun. Though i found myself not having enough time to adjust myself to get them to attach in the right orientation.
The crosshair is not 100% redundant, but it does not really explain where you are aiming, so it is a bit weird. I get that from a functional perspective, the crosshair makes sense, but you can really use it to aim your gun unless they are attached just right.
Though non of that takes away from it being a fun little (looter-)shooter, good job.