Great job! Lots of effort there.
Grafics are pretty decent, especially for a one man project. 6 months, amazing!
And it's quite ambitious, crafting, tutorials, creature codex and all. Monetisation even, dude!
Tutorial: less text please, reading slows down. (check for typos, too)
Icons: not always super clear; e.g. item stat icon in shop, not sure I really understand all of them.
Balance: Fells quite steep, from M6 on I had a pretty hard time
Mission background: Bit bland and unappealing. Bringing that to the punchiness of the other graphics would have great impact on perceived quality, considering how dominant that part is.
Runs a bit slow in firefox on full screen btw. Perhaps a fixed resultion/window mode helps performance? Graphics might come out crisper that way, too