Played co-op a few times today. Netcode is trash or nonexistent. It feels like old Quake matches where I need to think ahead almost a full second, predicting positioning, defense, and attacks. You are designated bait and support as the joining player.
It was still fun (novel) to finally play with a friend. Just know what you're getting into if you're buying this to primarily play co-op.
Odd limitations too. You can't access the mistle while another player is in your session, and you can't use permanent upgrade items like regen+. Simply have them quit, do what you need, and then rejoin. Such an unnecessary work around.
Add: Also, 2B - Rather than trying to recreate the "ballerina" outfit, I decided to go the t-shirt and skirt route I've seen in a few fan arts.