Thank you for sharing your game. Let me address some things:
Firstly, there is some stuttering happening while playing, maybe just on my end or due to web version, but it is there.
The combinations are a little odd, (Corn + Tomato = Blueberries?) though with so many combinations I suppose the randomness can be seen as a refreshing twist.
The music, although fitting for the dungeon battle theme, is a bit jarring and/or repetitive. I'd suggest something a bit more relaxing, as the main enjoyment of the game is the merging/inventory management aspect (You should remain heavily focused here)
This also ties into the sound effects and the pop up notification at the end of each battle. A little much, could be turned down a bit, or simplified.
Lastly, the battling mechanics are pretty wild. The numbers don't increase naturally per round, and can go from a simple shield for protection on round 3, to a sudden infinite health build on round 4. I'm sure you have plans to adjust those, hopefully.
That said, it was indeed fun! Let me address the positives quickly:
The backpack management genre of games isn't new, but always a welcomed theme if done right. Even the merging element in combination, not new, but very welcomed, and I believe you're heading in the right direction.
The art style is fair, it has a place here. The background could use some variation, as it is quite dark in comparison, but the vivid and bright shades of the items do make for a nice pop and it pleasant to the eyes.
The sheer amount of combinations is pleasant as well. I think you could benefit if you remove the ability to see every single combination on all items at all times, as it would give players more incentive to go for another run and stumble upon new combos. However, it is refreshing to be able to see everything up front. No mystery, just straight diving into the exact build you'd like to try.
I think you have a great game coming together here, and don't want to discourage you in any way. I'd love to see a class system introduction, but that can wait, there are more pressing matters I'm sure you're already tending to. I'm gonna keep an eye on this, I'll be here, excited to see it transform if you do decide to continue developing it.
Good game, good job. Best of luck 👍