Tutorial was a little bit dense and took me a little while to understand the mechanics, but once I fully grasped it... I WAS HOOKED.
Reminded me of the old days on d2jsp playing Ladder Slasher. Really satisfying for such a simple combat system. Watching the bars go up and my inventory multiplying was really fun. This definitely has a winning formula for expansion!
The shadow battle was a little bit anticlimactic, which is fine because it's a jam game and has to end, but if it kept going, or had some sort of "end game" system I could see myself continuing my playthrough :D
As for the tutorial, I think it just needs a bit of editing and color-coding keywords to help the player understand the game loop more quickly. It's just a lot to absorb in a short amount of time. Bold keywords, color code, and new lines to make it more digestible can go a long way. I really like the biome icons throughout, that was super helpful and made it easy to browse the inventory quickly, looking for my desired items.
For example, a suggestion for an edit to Tutorial 5/8 could be:
Equipped items are activated only by specific biomes.
Combat may fail without the correct items equipped.
Equip the correct items to scavenge more effectively.
You could maybe force the player to do some steps in order to proceed, like equipping a T1 item and starting combat before the next tutorial pops up, so players can learn one mechanic at a time. You'll see in my playthrough it took me 6 minutes to discover I could actually equip the T1 materials. Woops!
I'm glad I persevered and kept trying though. Really fun game loop, great job!!!