I've a question concerning this spell.
Isn't too much powerful?
Every spell can be powerful in DCC RPG. Every spell can be weak in DCC RPG. Every spell can f*ck up either the target, or the caster for days or a lifetime in DCC RPG.
You can paralyze (hold) every sentient being...
Unless they misinterpret the command. For example, I would hold out something if I heard that. Freeze might be better, unless it's against a frost wizard.
...that means basically everything from humanoid to slimes, undead or dragon. There is not even need that the target understand the language spoken as it works also on animals
Undead are usually immune to sleep, charm, and hold spells. Dragons usually have good saving throws. I don't see any problem in a mental spell being effective on animals or slimes.
So basically it can works as good as hold person, hold undead, hold animal and hold monster at the same time.
Again, no hold undead. The rest is true, but such versatility and powerful effects are also true for Charm Person, Sleep, Scare. This is a feature, not a bug. Casters get quite few spells in DCC RPG, and the spells already eat one or two pages each, so it's better to make them more general. Who would want to waste space and spell slots for seperate Hold, Charm spells per creature type? Especially in DCC RPG, where it's advised to come up with new and unknown creatures every time. Hold Undead or Hold Animal might be useless for several adventures, and you can't sit down every morning and change your spell repertoire á la D&D, you only have what you've learned at level up - if a bad mercurial magic roll already didn't make it near-useless already.
It seems too much powerful to me.
How do you manage it?
Sure, it can be powerful. If the spellcaster rolls well, or he spellburns some, and the target is not immune to the effect and fails the saving throw... Truth to be told, I've found an amped up magic missile far more powerful. A wizard in my campaign usually did a massive spellburn at every major enemy and killed them with a single blast. Then the rest of the party carried around him and took care of his weakened, useless body for days. Good times!