I did two runs, failed on the boss on the first but managed to beat him the second time.
I got caught by the "just one more turn, just one more fight" and did not see the time pass.
It's working well for a turn based battle system and I got hooked to the point I didn't see time pass until the boss.
Tank needs a taunt or a guard, he's a bit useless without a way to force the enemy to hit him. Thoug he still the save the early game of my second run because everyone else was dead but he took almost no damage.
In my opnion, maybe focus on better information of what the skills do (bleeding, passive skills without numbers) at the cost of less diversity. Less skills would also allow to have better basic but more useful characters.