I like all the NPCs that you have created and you MJ like protagonist. A quick think the I would change to improve your gameplay look is replace some of the intro dialogue with dialogue that better explains how to play. E.G.
- There's a killer on the loose. Find the weapons he's stashed to prevent the murder from happening
- How did this weapon get here? Let me put it away so no one gets hurt
- Anything that explains that you need to look for weapons around the map and pick them up before the "timer" goes off/the killer does
I also think that you need to create some kind of win state or give the player some kind of score in between runs to tie what's happening together and give the player a break between runs. Lastly, I think you could also see some kind of way to show the player how much time they have left until the killer finds the next weapon before you.