Hideaway now causes you to put the rest of the cards on the bottom of your library in a random order instead of any order.

If the spell you cast has in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.

Previously, permanents with hideaway entered the battlefield tapped. This ability has been removed from the definition of hideaway. Older cards have received errata to have an additional paragraph that reads "[This permanent] enters the battlefield tapped," and they now have hideaway 4.

Collector's Cage's last ability looks at the creatures you control as it resolves to determine if you can play the exiled card. For example, if you control a 4/5 creature, a 1/1 creature, and a 2/1 creature, there are three different powers among creatures you control.

If you cast a spell "without paying its mana cost," you can't choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the spell has any mandatory additional costs, those must be paid to cast the spell.

Any player who has controlled a permanent with a hideaway ability since a card was exiled with it may look at that card.

You choose whether to play the exiled card as Collector's Cage's last ability resolves. If you do, you do so as part of the resolution of that ability. You can't wait to play it later in the turn. Timing restrictions based on the card's types are ignored. However, you can never play lands on other players' turns.