Playing an exiled card causes it to leave exile. You can’t play it multiple times.

You may look at and play cards exiled face down with Gonti’s last ability (and spend mana of any type to do so) even if Gonti leaves the battlefield. If another player gains control of Gonti, that player can’t look at or play cards already exiled with Gonti, and you still can.

If you leave the game, any remaining face-down exiled cards remain exiled face down indefinitely. No player may look at them.

You pay all costs and follow all normal timing rules for cards played from exile with Gonti’s last ability. For example, if the exiled card is a land card, you may play it only during your main phase while the stack is empty.