Shang Tsung’s shapeshifting, dark sorcery, superhuman physical, and martial arts should put him at a high power level. What power level do you consider him to be?

Probably an Alpha-Level Mutant. Such as Namor, Rogue, or Storm.

And Black Adam, Wonder Woman, and Superman’s power levels?

Cosmic-leveled. They’ve taken on powerful characters. Shazam, Darkseid, and more.

Doesn’t Shang Tsung’s shapeshiftng gives him more of an advantage if he morphs into them?

Well, I thought the same case for Mystique from Marvel, but no, not at all. Shapeshifting confuses your opponent, it doesn’t give you an advantage. I also think when you shapeshift into someone else, you only receive a portion of their powers. Like, Mystique can shapeshift into Sandman, but isn’t able to receive all of his powers.

Shang Tsung’s gameplay gives him access to all their powers plus his own. I never thought Mystique doesn’t gain every power no matter who she changes into. Is that still confusing?

It is. Should be able to have anything despite who you look like.

Fine. I still think he has certain chances to match them equally.

If you say so.