Trying to stage a comeback when you're losing fights is really difficult. I think the slimes just aren't giving enough gold to justify fighting them. 

Renamon would benefit from either starting with or learning a multi-target skill at level-up, considering that she faces very quickly groups of enemies, and enemies have high HP for the moment.

Corruption skills cosuming MP makes using normal skills unavailable. Considering that 2 of the corruption skills require 100 TP, which takes several turns to pool, I think it would be better if corruption skills did not use MP, and worked with TP in the same way as "limit breaks".

I think the game would benefit from a weakness system, to speed up battles. You could go with the usual four elements, or you could go with Cybersleuth's triangle (base < virus < vaccine < base). 

Related to the two paragraphs above, you could make it that normal skills are unavailable while in "corrupted" state, to give the player some thinking room as to whether they should rely on skills or on corruption skills.

Having Renamon start at 1HP after a game over is too harsh, in my opinion. As it currently is, it is easy to enter a losing loop where the gold you get goes to potions instead of skills or gear, until you're out of potions and gold.

Finally, I think that it would be nice for the slime and the slime wall to have game overs, like the slime boss, and it would be nice for the slime clone or the wall + clone combo to have their own grapples. As a general rule, you can't go wrong with more grapples and more scenes, seeing those is why most people will play your game.

gameover scenes when defeated by enemies, especially with different condition.
fights are very difficult, theres nowhere to save and restore hp/mana. and once you level up enough grapples start to miss. scene for being grabbed by floor slime once already wearing slime suit.