Hey,
Thank you for the great constructive feedback! All your points are relevant and I agree with most of your suggestions, they will help me balance the game.
Coins right now are indeed quite spare, especially in early levels. The goal is that the first tier of shop upgrades is easily accessible, while the other tiers are hard to obtain unless you stack the rare upgrade that drops more coins, if you feel like your character is strong enough. Giving bonus coins based on the level achieved is something I will try.
Running in one direction or running in circles is something I'm trying to avoid with the spawn system, I'll try to think up good ways to avoid that player behavior while still keeping an infinite map.
Right now some builds work with staying in melee range, but I agree the range is low and the "ranged build" feels much safer. I plan to add sword range upgrades, just need to do the art for it (I don't want to scale pixels).
I've noticed the same issue about projectiles, initially the gameplay was very focused on projectiles and parrying and I have a few ideas in mind to solve the problem you talk about.
Good idea about the bleed stacks. Right now I don't mind too much that it isn't capped on normal enemies, since it's one of multiple paths to get enough damage to deal with late game enemies. It's capped at 1%boss HP per tick.
About contact damage, there already is a limit, but I agree it sometimes feels too punishing and fast, I'm iterating on ways to change that.
Buying the whole shop will definitely make you OP for this version of the game, but might allow you to test out builds and hidden upgrades. Also, the second boss is stil waiting for you ;).