Unwinnable without luck. This is an auto-battler where your only input is what new ability you gain before each fight. Each of these abilities are passive; your only action is to sometimes cast a very costly spell to regain health or deal damage to enemies. It's a very barebones system, crippled by the fact almost all those passives are really weak, and only have a marginal effect on the outcome of a fight unless you pair them with similar passives.
Some of them heal, some increase your damage output, your attack speed, your mana regen rate, etc... But, again, those buffs are so weak you might not see the effet in combat, either because you win quickly before they can build up, or because you lose, because every enemy hits like a truck.
There are passives that increase your evasion, and you better believe you're gonna need them because every hit counts. The problem is, one of the ways to get those passives is random, so you might not even get the passives you need to win a fight, and so you end up with abilities totally dissociated from each other that you cannot exploit, leading to an unwinnable run.
There's too much left to chance, and as far as I'm aware, I don't know how to use the items you gain as rewards, if they're even equipable at all.
The artstyle is nice, but honestly it's not worth going through this game. Try to win the first boss fight to unlock the cheat codes, then go find the guide in the comments section to unlock the gallery and get your fix this way, it's much more bearable than having to play the game at all.