OMG thank you so much for this long review !
To begin, I'm so glad you enjoyed the game and you already played it multiple time, that sounds crazy to me !
A lot of things are rushed or not implemented, that's the jam life haha. I didn't manage to take the time to implement a good death/checkpoint system so I chosed to just not let the player die, I think it was an ok trade for a jam game. Actually there is a sound effect when you take a hit, but it's mixed way too low in comparison to the music. Again, it's something I rushed and didn't take time to adjust in the last minute of the jam. There is also 0.5s of invulnerability frames, and I'm not aware of any probleme with it but I'll investigate a bit, since I want to work on the game again to polish it a little more !
I'm so glad you enjoyed the boss patterns, the graphics and especially the music made by my friend who work with me on this game !!
Thank you so much again for this review !!