Got through the Ruin Sentinels and Belfry Gargoyles today. The former was one of the best bosses yet. Smart design and fun to fight once you got the hang of them. Stuck around to help a few people co-op it so I could experience it a couple more times. Very satisfying.
Not so much can be said for the Gargoyles. It was just more of a "How many of these things can we throw at the player until they throw the controller down in frustration?" kind of boss. Not really interesting or fun to fight. I'm glad I had some Gold Pine Resin on hand - my Bastard Sword powered up by that made short work of each Gargoyle before I could get overwhelmed by them.
The Belfry Gargoyles are actually a returning boss from Dark Souls 1. Only in that game, I believe they were capped at two gargoyles, IIRC.
I actually quite like the battle in DS2. I had four gargoyles on the field at once, with a fifth joining after I killed one of them. It was epic ducking and weaving past their lances, lightning bolts and fire breath.
And yeah, Ruin Sentinels are great. I had some cool moments where they both did their spinning attack, so I was rolling one step ahead of a whirling blender! Another time I was rolling backwards as each slammed their halberds repeatedly into the ground. Bam, BAM! Bam, BAM!
You mentioned making yourself available as a summon so you can play them again. So does that mean people can summon you to help fight that boss even after you've already beat the boss? I'm still not clear on how summoning works.
I'd love to be summoned to help with the Looking Glass Knight fight. Or better yet, to summoned by the knight itself to fight as one of his Dark Spirits! (Yes, the fight can be a boss and two human fighters vs. the player -- nasty!)