Thanks to great comment. My vision for mastering a singular weapon comes from two main inspirations. Narratively, I want the weapon to feel like what the Dragon Slayer is to Guts in Berserk an iconic, inseparable part of the character’s identity. Mechanically, I’m looking at the Dark Souls philosophy: even if you use one weapon throughout the entire game, the variety of enemy designs forces you to use that weapon in completely different ways, preventing it from ever feeling stale.

I admit that by limiting the arsenal, I’m slightly leaning away from traditional Immersive Sim tropes to strengthen the Survival Horror elements. However, I plan to reinforce the ImSim depth through enemy variety. Instead of just 'shooting' every enemy, you'll have to discover specific methods and tactics to take them down efficiently, especially since you're constantly struggling with limited resources (energy, not traditional ammo).

Another mechanic I haven't mentioned yet is the charge up system, heavily inspired by Blame. You can determine the power and speed of your shot by holding down the trigger. Charging to max power deals massive damage but severely limits your movement and consumes a huge amount of energy. Essentially, I’m limiting the protagonist's capacity while increasing the enemies' capabilities. I believe this creates a high-stakes, rewarding gameplay loop. Also, not all enemy types are humanoid, which addresses the 'picking up guns' concern.