This reminded me of the Z.O.E games and that was a great feeling honestly. I loved messing around in the versus modes that series had and I think that this could really do a lot to fill in those long vacant shoes. A faster but weaker projectile could probably go a long way to making the shooting feel more rewarding honestly.
Possibly out of scope but I kind of also wanted if instead of RMB being combo you hold RMB and that locked you into a 'melee' stance and you could use other buttons to layer on different physical attacks (air launchers, slam into ground, circular spin, etc). Releasing RMB would then return you to your normal shooting mode. Again, probably out of scope or even against your personal design plans but just wanted to bring it up.
Really good thing you have going on here and I hope you continue to work on it! Thank you for the demo!