Not bad, the skills are nice but you'll definitely have to change a lot of thing before using one boss from this pack, some things like skins, health bar etc are missing so you'll have to put it yourself, the skills aren't balanced at all so you'll have to change that, some skills do 1 heart of damage when some literally one shot you.
The pack is cool if you know how to make a boss but you don't want to waste your time doing 12 bosses, if you don't know how to avoid this, it's not plug and play. You also wont have any support as the owner doesn't respond on discord.