So... due to the source code having serious performance issues, I'm gonna try to recreate the project again. It's gonna take some time, but I will try my best to do it as fast as possible.
Ok, so during my playthrough of the game, I noticed some things that just didn't look good. So, I decided to fix them and now the game should play all good.
If you notice any other bugs, please leave a comment under this post.