Thank you for your video and feedback!
"The guns feel utterly useless against two thirds of the enemies I encountered due to the dissipation of the projectile, the lack of aim and the height of some of the enemies"
That is your first gun and it is used primarily to stun enemies, The limitation of the aim system is a design choice to create new strategies to deal with out of sigh enemies(trowing grenades, using a sniper rifle, using drones or getting to a higher place).
Btw, why didn't you use the dash? It's definitely would help in the combat!
"but it seems, to me, to clash harshly with the resource based ammo and healing system. "
That is something I'm still testing, indeed right now this system can lead to a soft lock if the player tries to play like a hack n slash... so I'll try to improve if until the final release
again, thank you for your feedback!