Very fun for a build this early! I noticed in the page photos, there's a "tutorial" button but I couldnt find anything of that sort in the actual game. It'd be super helpful. For example, in my first couple of runs, I thought that the synergy bonus only worked if both mons were in the same lane, which is the opposite(don't worry, learned it later on). Or that the continue button wasnt outright cheating, but that it was spinning for another retry.
The usage of enemy items in lanes provides a fun twist, while for the most part being fair. The weight mechanic provides a lot of incentive to not just stack points like other roguelikes of this genre. One small thing that would be helpful would be warning that the negatives of some of the items can be affected by multipliers. On one enemy, I got a 3X synergy bonus, but unfortunaly one of my lanes had enemy blood, which means I was very far in the negatives and had to give up on that life ;-;
Like a previous commentor noted, the balance overall could be improved upon. For example, on my first successful run, I used the black knight. While the weight of the maces was helpful early on, their extremely low point value while also not providing direct synergies with anything else made them a nuisance later on. I feel like it's a similar sentiment with all of the non-consumables.
I've seen some of the mons that benefit from having a larger team, but there just isn't any way to accrue enough gold to afford more mons while also keeping them all up to snuff. While this might change once the game becomes longer, the sheer utility of something like "lord mutant" feels too large to ignore.
So far, the relics in the game are somewhat "vanilla" relative to roguelikes such as Die in the Dungeon, but what's here so far is quite useful, such as the auto evolving egg. Perhaps relics that synergize with mon effects might provide spice e.g. maybe relics that add more weight to elemental buffs.
Overall, the game has a lot of potential and I can't wait to see what it can become! Definitely will keep up with this game.