Okay, so did some more grinding, maxed out my levels...
You have two skills that are glitched. One skill is supposed to give you +25% Recovery. Instead, it gives you -75%. For some reason, Thunder combo does the opposite and makes the recovery skill heal much more? (Not sure why as it should be working properly).
The blue tunic is basically useless as it only affects Mage main class at high levels (minimum of 100 MP) and only 1 per turn.
Regeneration is honestly very annoying when the enemy can spam it. It makes Mage very much useless as even at max level, you can't do enough damage with mage and even if thunder 2 worked properly, you only can use thunder 2 3 times (and the recovery decrease of 20% wouldn't really do all that much..
I ended up having to focus on poison, but that is basically relying on luck.
Game just ends pretty abruptly.
Another issue is that you have a lot of grinding required in the game to even get those poison skills. Gold gain is very slow and limited even with the merchant class.