Thanks for trying our game, and thanks for the super thorough feedback. Really appreciated!!
Regarding the "blue round alien", he's a EyeSpike, one of the creatures that inhabits the upper layers of our Hell. He's invulnerable when he's right-side-up, but you're able to rip them out of the platform like a sea urchin if you hook onto them while they're upside-down.
I think he didn't do damage because I already killed him before he was perhaps able to detect me? So maybe that's why it didn't do anything, I'm not quite sure but it was why I thought he was one of those environment pet thingies haha. Regardless, every one else I encountered after that moment did do damage so maybe I wouldn't fret it. But just to answer you, it was the very first one I encountered in the blue area, on a lone platform on my way to the top right of the screen.
