I really like the bank shot mechanic a lot and there's a nice variety in the kind of effects you get from the slot machine.
Using your ammo for the slot is a really good idea in that it sets up a cool risk/reward factor where you trade off some defensive ability for a chance of a power up. On the other hand, since it's the only way to get ammo, you're kind of forced to 'farm' chips to not run out, which isn't really ideal for an action game.
One thing i will say is that having a risk of simply running out of ammo and losing made me really invested in the outcome of the slot, which is something i think a lot of the other jam games which try to minimize the randomness are missing.
One thing i'd reccomend looking into for pixel art games is having a consistent resolution. There's a lot of different sizes, and it looks kind of odd when, for example, the pixels on the slot machine are twice as big as on the player character. I also think some of the sprites are getting slightly warped due to the screen resolution not lining up with the sprite resolution properly.
Other than that, i think the sprites are all farily nice, and the use of lighting really helps make things pop and look polished.
Overall, a nice experience with some good ideas.