I really appreciate your comment and thank you very much! It means a lot to me that you liked my project!
Previously, the player's movement speed was a little higher, but the idea was that: after each collected major soul shard (dropped by demons), the Player's movement speed and damage will increase, and his health will decrease. As you gain more power(speed and damage), you lose something valuable(health).
Unfortunately, I didn't really manage to implement this well in the project. ;)