Its been the second time that i encounter what seems to be a bug:

The opponent would cast Raptorous Moments Literally for free with no way of doing it, like no Zero mana cost enchantments or anything.

So thats 6 mana cost Raptorous Moments gives them back 5 mana

Plus 8 direct damage as the second spell Traumatic Critique for 10 mana

So thats 6+10-5 = 11 mana spent

How is it possible that the opponent wins the game with only 5 mana spent?

I swear no mana tokens used, and also i would have lost anyway because he had 12 mana, enought to cast everything anyway, but its weird.

First time it happened was a 100% guaranteed win for me the next turn and no way the opponent would have won, like in this case, but I didnt bothered then.