I had am embarrassingly interesting loss to a 1HP Arena deck yesterday.
-Started without a single creature but a lot of Supernovas and a QT.
-3 Turns in I draw my first creature - Lava destroyer, but not before it plays a Shard of Divinity, bringing it's HP up to 17.
-Lava destroyer deals 7 damage, AI plays Maxwell's Demon. Lava destroyer deals 9 (grew) bringing the AI down to 1 HP before it gets Paradox'd.
-I draw Otyugh and play it, unable to eat the Demon I end my turn. AI plays Diamond shield and random low-hp creature.
-I draw Ulitharid and play it. I eat the low-HP creature. Unable to get passed Diamond shield for the last point of damage. This continues for 2 more turns until my Otyugh is at 3 damage and will eat my own Ulitharid next turn if needed to win.
-AI rewinds my Otyugh and uses another Shard of Divinity.
Can't remember the next few turns but more rewind + black holes + shards of divinity lead to me being unable to deal enough damage and unable to play Otyugh for crowd control to overcome his now higher HP and increasingly many creatures. Anyway suffice to say, if the AI gets a good draw and you get a not so good one, you can still lose to 1HP decks.