Having a blast with the single-player but the invincibility frames on glory kills keep screwing with me. Most of my deaths are coming right at the tail-end of the glory animation, where I get nailed by something before I even have a chance to move (and I'm playing on Nightmare where taking one hit does big, often fatal damage).
Glory kills seem very useful on the higher difficulties both for the health pickups and to conserve ammo, so you're encouraged to use them. I'm happy to see they don't hurt momentum as much as I'd feared, but it's hard to know when to use them safely when taking one random fireball knocks out 70% of your health, and you don't always know where every enemy is. They'd feel a lot more comfortable to me if you were still invincible for a few frames after the animation appears to end.
Glory kills seem very useful on the higher difficulties both for the health pickups and to conserve ammo, so you're encouraged to use them. I'm happy to see they don't hurt momentum as much as I'd feared, but it's hard to know when to use them safely when taking one random fireball knocks out 70% of your health, and you don't always know where every enemy is. They'd feel a lot more comfortable to me if you were still invincible for a few frames after the animation appears to end.