How many have you unlocked? I just got the second unlock, the Fat Mexican (it's okay to say this, because I am a skinny Mexican).
I am really really enjoying this game! And is it just me or does the game get harder on each unlock? After getting the second unlock I noticed that the first battle of the first stage, was harder - the enemies had more stamina bars. I actually lost on that first battle, before restarting and getting through it fine.
Overall I think this is great - but I am curious at what point does it get "you better had gotten the right spells and items" at this point or everything is going to be crazy hard and you probably won't make it. I'm on the 3rd stage after the 2nd unlock and it got really hard. I'll give it another pass tonight and hopefully make it further, but the enemies have so many stamina bars and I don't feel like I am equipped with enough good spells to take down that many stamina bars at once.
... You can actually save scum the battles in this game, if that's not already obvious. Before you take the final death blow just Home Menu > Quit and restart, you'll be back at the same battle.
EDIT: Also, I'm so happy someone else posted in this thread to bump it. I just got it on Friday and I'm super super enjoying it. But the 3 page thread tells me that this isn't going to be a mega-hit, which is too bad. It's $10 Switch version at GameStop right now, new! Definitely worth everyone giving it a shot, and it has a trade-in value of like $8, so you're only out a couple of bucks if its not for you!