This has a fun core loop, with an admirable variety (and amount) of both loot and enemies. I like the narrative premise and the slimes themselves, too.
It wasn't clear to me what data I should be using to strategize most of the time though. I didn't notice particular stats for the individual slimes, the items (other than the item levels), or the enemies. The initial loadout for each slime seemed to be an intentional recommendation, but the reasoning behind why that loadout was recommended wasn't obvious to me. Eventually I noticed tags for types of damage, and these tags also appeared associated with different characters/enemies in different boxes, but I couldn't tell whether these were strengths/weaknesses/attacks/etc. I wish hovering over the icons mentioned context like this (i.e. what the box/location means) in addition to the meaning of the icon, or that numeric stats were shown.
The UI also feels a bit overwhelming. There are so many things and so many slots, there are tabs and filters and scrollable regions. Most of the time I felt like I just wanted to give things of a certain type to a certain slime, but the UI doesn't quite feel designed for this as the primary interaction. The default feels like pick up one item and put in one slot of the current slime then switch to the next slime, or be lazy and just dump everything to one slime. Doing things one at a time gets to be more complicated as the loot piles up and you have to start scrolling to reach the one free slot. There's a lot of mousing back and forth that feels unnecessary. Filtering is hidden under a sub-menu. Also about 40% of the screen seems to be filled with the belts of all the slimes all the time. (Is that where I should be spending more of my time? Maybe it is, I'm not sure.) Since the loot and loadouts seem to be such a core part of the game, I feel like the UI here should be refined to reduce friction as much as possible for normal interactions. Does the order matter? Maybe when you have a slime selected, you could just click the item to drop it in that slime's last slot, instead of clicking the item, then clicking the empty slot. Since I'm not super clear on the strategy, I'm hesitant to make specific recommendations for improvement, but I'm confident there's a lot that could be polished here.
I hope this doesn't come off too negatively! I had fun and I think there's a good core here. It does feel like it's worth continued development! I just feel like refining the UI/UX (both for communicating the strategic elements and for dealing with loot) would help me get a lot more out of the current gameplay loop.