Two things that I hated were the fact that item containers were hard to destroy (wich I understand is a reference but it ain't fun when there's too many)
And the Marisa's hitbox compared with the needles, it's so hard to hit her that the final battle becomes an accuracy test.
Other than that I had a great time on stream, not a big Isaac fan but I love the game and it's difficutly, and the cards seem balanced enough to not pick only one side, so congrats for the result.