Make it Reality Spasm instead? Neither is rare worthy imo.

Can I both untap 2 creatures I control and tap 3 creatures opponent controls if I cast this with X = 5?

Ambiguous as written; though if written so that explicitly you can then limiting to creatures-only is a valid reason for this being the same cost as the version that cannot but hits any permanents.

Suggested wording for that version: "For each of X target permanents, you may tap or untap that permanent."

Originally, I threw up a suggestion of this spell instead making X copies of itself. But admittedly, Gigadrowse was rather good. But mostly because it won counterspell wars, which Reality Spasm is only mediocre at.