Updated to v0.015, you can now scroll through your weapons by assigning NextGun and PrevGun to your chosen keys or mouse controls in the Options menu. Enjoy!
Yes, really nice! This plays far more fluently. You can easily switch to the masher for boxes to conserve ammo and easily switch to other weapons when running out. I've been playing this far too long, it's so satisfying.
One improvement I would make is to have the shotgun use reload as well. I sometimes find myself out of flow when clicking the wrong button.