You are correct...the game isn't polished as it was a two day game jam exercise for me...the keyboard controls are definitely trash...I use a XBox One controller to develop and it works for me.
The food item on right is a carrot which gives you night vision so you can see clearly underground...I didn't make the bottom black out black so you didn't have to get the carrot upgrade. In Metroidvania games you sometimes can skip upgrades and complete the game so I thought I'd leave it like that. The bottom is too easy...originally it was so hard it took me 5 lives just to get the upgrade so I nerfed it.