One of its neat aspects is deciding whether/when to activate the Witch, specifically the fact that the Witch — when used to block your opponent’s (unseen) move — forces you to both take her off the table (precisely what your opponent would do anyway if playing a Fighter card) and discard something from your hand (what you’d be forced to do anyway if your opponent is playing a Thief). So blocking with the witch is actually more of a hardship for you than letting your opponent play, if your opponent is trying to play one of those two out of four card types.

I suspect that if played with a live opponent, the interesting bit may just be the endgame, during which you might feel forced to use your witch lest your opponent be able to end the game with their next move. This should lead to a bit of a psychology-loop in which your opponent, knowing this, will be tempted to play something other than the winning card (unless they have two of them), under the assumption that it’s going to be blocked anyway, leaving the winning card still available for their subsequent move. But you, knowing that might be tempted to not yet use the witch (unless you have two of them), so it’ll still be in play on their next turn when they might really go for the win. Etc. etc.

It also has a neat balance of public and private information: a witch needs to be on the table already to be used. Cards sent to the past are visible to all and what you rescue from the past can be seen by all. Neat.