I created a health system for the goblins so they do not die right away. The players are required to shoot it 10 times for it to die. This will increase the difficulty of the game. Since the quest is "collecting" goblin bodies rather than destroying it, I made it trigger a dying animation when the goblin health reaches zero instead of it being destroyed, and the players can collect the goblin bodies only if it is dead and the quest is active.

I also made reload system when ammo is shot for the player, so he/she cannot constantly shoot. After each shot, the player must wait around 0.5 seconds to take a second shot. This is also to increase the difficulty. To make the players better explore the area, I slowed down the running speed when left shift is pressed.

My group and I also made the dialogues of the NPC more interesting by making them match the storyline rather than for it to just say "bring me this."