I'm looking for some feedback on my game Tourmaline, particularly on the gameplay and whether or not playing the game is an enjoyable experience (which is subjective, but your opinions would be appreciated). The people I have had test the game already have had varied opinions on a lot of aspects of the game, and I would like to know how other people feel as well. 

As an example: One of my friends played the demo and said they disliked how there was no checkpoint before the boss, and that you had to replay the level to get another try. Another friend said they did not mind having to play through the level again.

I've only had three people play the game at the moment, so some more feedback would be appreciated

Thank you for your time, and here is a link to the game: https://duke-of-souls.itch.io/tourmaline-demo