It's a good setup, but there's not really any tension. I think you can improve on the following points:
- The imagery is nice, but there's way too much of it. If I were you, I'd cut out like 75% of it, leaving only the most evocative details, and focus on what's happening instead. I'd have stopped reading after the first paragraph if I were casually browsing.
- You stop to give us exposition about slugs, how you kill them, etc. You should be showing all of this through the action.
- Dave seems very blasé about hunting this slug thing. He just kind of dispassionately informs us about what it is, how you kill it, and what happens, but there's no sense of urgency to the situation, so I'm not invested in what's going on. Dig deeper into his emotions. I don't know about you, but I'd be pissing my pants if I were fighting an evil slug monster.
- It might be nice if you can come up with a better hook. A good first sentence or paragraph should have some kind of unexpected or ironic twist that intrigues us and makes us want to keep reading to understand what's going on.
I also personally don't like the narrative conceit of killing the narrator at the end of an introduction. It's been done a lot, and it makes me feel like I just wasted my time reading about this person. It also makes your story really easy to put down because I have to expend the initial energy to get involved in the narrative again.
