The level of polish here is bonkers for a one week jam! Y'all did a great job overall.
Since you're developing this game beyond the jam, I'll go into more detail about the parts that didn't work for me. The pattern that I fell into during the shootouts was: leave cover, spam left-click to fire all of my shots into the nearest enemy asap, get back into cover, reload. Reloading took longer than the other steps combined, so I spent most of the game sitting behind cover and waiting. However, I don't necessarily think the reload should be shorter! I think there were a few other factors that were pushing me towards playing that way.
First of all, the enemies would usually chill and let me do this, so I didn't feel pressure to try a different strategy. I'd be interested in seeing a version where the enemies flank you, flush you out with dynamite, and/or shoot at your cover to damage it.
Second, it seemed like it took multiple shots to kill each enemy (except for the rat bullets, which seemed to be a 1-hit kill). I could be wrong about that - maybe most of my shots were actually missing - but regardless, it felt easier and more reliable to empty my whole gun, especially because I knew I could safely reload in cover. This took away from the fantasy of being an accurate, coolheaded gunslinger, and it also made the bullet effects less important because my plan was to hit each enemy with everything I've got.
This leads into the last issue I noticed, which is that there wasn't enough incentive to be strategic with the bullets in combat. In the planning phase, there was a bit of strategy (e.g. putting 'lasso' just before 'buckshot). 'But once I was in the thick of it, I didn't think it was worthwhile to wait until I could damage multiple enemies with a single 'arcing' or 'piercing' shot, or hit a fast-moving enemy with the 'ice' shot, or move in close before using 'buckshot'. It was faster and safer to shoot everything at whatever enemy I had a good angle on than to plan each shot out.
Ok, that was a lot of criticism, so I want to stress that I do like the game! I'm looking forward to seeing more of it!