When playing a card hidden, do you need to pay the rune cost in addition to the power requirement?

Ruling: When playing a card hidden, you only pay 1 power in a battlefield you control. You do not pay the card's normal rune cost or energy cost. When revealed later as a reaction, you play it without paying its cost.

Sequence:

• Pay 1 power to play the card hidden in a battlefield you control
• On a later turn, reveal it as a reaction without paying its cost
• When played from hidden, it can only target units in the battlefield

Nuances:

• All hidden cards must have the same hidden cost (1 power) so opponents cannot differentiate what is being hidden
• The normal card cost (energy and power) is only paid if playing the card as a regular card, not hidden