I enjoyed playing this. I like the added depth from looking for and swapping out upgrades. Although I regretted picking up the shotgun as I felt the previous weapon was a lot better - would be cool if you could cycle through weapons.
I think the game would have benefited a lot from a bit of visual feedback e.g. when you pick up items (swap body parts). Maybe something that adds difficulty like limited ammo. Also, the music makes it hard to hear the sound effects - a bit of adjustment maybe.
The variety of items were really cool and made me want to play more (especially to see if any further guns). I think you did well in making this fun, good job :)