It's sadly a poorly balanced game. I played as a priest. I reached the CEO I can't beat because he's mauling me like a beast and can't do any level up, so game over.
My biggest problem is the way restoration works : what's the point of healing yourself if you only regain 2-3 hp you'll directly lose when your ennemy attacks? The same with potions, but at least they don't use your attack turn.
The other problem is the fact this game is waaayyy to much luck based, I didn't encounter the trainer until halfway through the game, so I get riped apart on every other level with my puny 9 hp and -3 attack. And it's of course a vicious circle : the latter you encounter the trainer, the less money you have because you die often.
It gets better at the end because I found a +10hp armor so my healings finally serves at something, but even then I only healed +7 against the boss who hit at -8, so once again the skill is useless.
So if I have some advice to give : go with fixed HP heals or multiplies the hp by 10 and damage by 2 for everyone. Also refined your "leveling" system. If you don't want to go with points, then maybe add a bank system with a tax of 10% where we can store our money for when we encounter the trainer. Finally I would give the opportuny to leave the tower and restart at lower levels (a check point every 50 level?) so the players can at least grind if they really need to.