Had fun messing around with this. Once I noticed the bug with rerolling shop each time you walked up to them, I decided to try and do a melee only build. Unfortunately, the mech boss doesn't take damage from your melee. (Which I assume is because typically your melee freezes the target during the animation, which would trivialize the fight).
Fun to mess around with different builds, I'd recommend trying to add damage falloff to bullets. As, I managed to beat the game on my second run by getting the SMG and just spraying around the screen which led to me just killing enemies offscreen then collecting their oil. Also the mech boss has a tendancy to freeze and stop moving.
Had fun with it :D
Viewing post in Oil Thief jam comments
Yeah, I had some issues with meleeing the boss, and was trying to figure out a good balance (maybe letting you do it for a few seconds before getting pushed off) but couldn't get it working in time, so I just cut it. If I keep working on it, I'll definitely look at the balance again, and weapon damage falloff is a solid idea for fast firing weapons. Thanks for checking out my game! I'm glad you had fun :)