Thank you for all of the kind and useful feedback! Everything was made by me other than the music because I am no composer. I was only able to get this much done because of the Engine I used which is Gdevelop. It has a lot of limitations but it allows me to make small-scale projects like this rather quickly when compared to more complex engines. The movement, for example, is coded for me so that I just have to tweak values. I really like your suggestions such as footstep SFX and a difficulty curve. If I was to revisit this project I'll definitely implement that.