>>11887836
Yeah, subweapons don't really work with the same way as other enemies because he has iframes after you hit him.
Strategy is: hit him, crouchwalk to the side and stay crouching while he lands besides you, be careful with the spear. You want to be close but not too close, then after he attacks (and doesn't hit you because you're crouching), whip him, while stil crouching.
Then repeat this until he enters his second phase which is where the real difficulty begins.
Hit it, then walk immediately to the furthest from where he's gonna land. Walk away and jump over the small platforms, or jump over them and go to the edge of the screen if Slogra is landing too close to you. He will start doing his beak dive attack, this is very quick and he can do it consecutively. Keep a distance, and whip, then again, as soon as you hit him, walk all over to the other side. There's a rhythm to it, you need to be quick and pay attention at where is he gonna land, if he's landing close to you, he will definitely try to dive as soon as he lands, so jump! And keep walking away, only turn back to whip once you're sure you're at a proper distance where he can't touch you. good luck!

>>11808161
Yeah, it's on the part right after the chandeliers