Hello! Thank you so much for the criticism, this really helps us make better games in the future! I do admit a lot of this game was unfortunately rushed, and a lot of planned content was cut in order to make the jam deadline. There are several bugs, features, and tweaks that I plan to make or fix in future non-game-jam versions of the game.
However, I would like to say no third-party engines/templates were used to make the game. The engines used to create this game were Clickteam Fusion 2.5 as the main engine, Scratch for the art, and BoscaCeoil was used for music made by me and Vanouper. I'm not exactly sure what Mark used to make his music. Difficulty balancing is definitely a planned update for the future because I haven't even beat hard mode yet personally and I made the game. As for the story, the Dragon Master does appear again as the Stage 4 boss, although this is never explicitly mentioned in the game. I plan to add boss names near the bottom of the screen similar to Dark Souls, so you actually know who you're fighting. I might also try to make some of the bosses a bit less tanky since I personally felt it was a bit tedious. You're absolutely right about the hitbox thing because it does exist but its barely noticeable since it's the same color as the character.
If you have any other suggestions that you would like us to implement in future games or a remastered version, you can let us know! We are very open to new ideas to help diversify and improve our games. We will make sure to keep your criticisms in mind for future games. Anyways, thanks for the review! :D