Cute art! I enjoyed the music as well.
Some thoughts:
The controls felt a bit floaty and imprecise. There was momentum that persisted after holding a direction which may be more physically accurate, but typically doesn't translate well to a shmup style game tha rely upon very tight controls. I'd recommend using transform translations for this style of game vs unity physics (rigidbody - add force stuff).
The secondary attack was a bit confusing. I wasn't sure how I should be using it, as colliding with an opponent in a shmup game typically means you will take damage. I had at least one time I used it and ended up taking damage. I think the concept of giving the enemy a "high five of death" is pretty sweet, just needs some better implementation. Perhaps instead of swapping weapons with E, the player holds down space to charge up and then when you release they shoot forward. I think this would feel better over all.
As others mentioned, the feedback on hitting enemies should be cranked up a bit to given the theme of the jam.
High points on creativity, art, and music!