Devil-O-Angel

(Eldritch horror/otherworldly) Both the soul (player) in Deltarune and the pinhole god are explicitly eldritch horrors. It's more obvious in Iron Lung because we're put in the perspective of the human protagonist (Simon) as he's tossed around by influences he can't understand/grasp and finds incomprehensibly immense (the only time the god is visualized is when its a single, enormous eye floating above an ocean of blood, shrouded in clouds like geez we get it). In Deltarune, we the player are an undeniably diegetic part of the game's canon universe. Our existence is incongruent to our human protagonist (Kris), and we even clash with them on multiple occasions. In our perspective, this is fine, a cool twist on the player/game relationship. In the perspective of the game characters, however, we are an unpredictable, unstoppable, enigmatic entity possessing a human teen (alluded to as a demon, even). We can seemingly never lose a battle, time travel, and exist on a higher plane of existence. Even though the soul has more goofy, Tom and Jerry type shenanigans with Kris compared to Simon's "religious experience", there's no denying its otherworldly nature.

(Red) Both deities are heavily associated with the color red! The soul is the embodiment of OUR determination, passion, and willpower. Thus, it is a red heart-shaped-object. Very iconic. The pinhole god is red themed because it's residing in the whole blood ocean(and maybe created it?); it's hard to separate those two.

(Godlike) It's heavily implied that the pinhole god caused the Quiet Rapture, made moons with oceans of human blood, mutated the hell out of people who go into said oceans of blood, and made a deal with Simon to 'live'. We don't exactly know what it can do and how it does it, but we do know it's powerful enough to snuff out every star and habitable planet without even meaning to. The soul isn't quite as omnipotent as the pinhole god appear to be, but looking at its feats (our feats), especially in the weird route, you could start making some parallels. Because Deltarune is just a videogame, we can access its code and edit it however we wish, effectively manipulating its world. We can also delete and create save files, which could be interpreted as destroying and creating entire timelines/worlds. In the weird route, we change the course of the story, finding creepypasta-esque glitches that diverts Deltarune to its Forbidden Path. In the process, we break the mind of Noelle Holiday, exposing her repeatedly to The Horrors and changing her until she's driven mad. Sound familiar? For fucks sake they're both called 'Ellie'

(Limited perspective) The pinhole god is an ignorant being (bit of an oxymoron), as the name suggests it perceives the world of Iron Lung through something like a pinhole, a tiny gap in reality which could relay only so much information. (Assumedly through this misunderstanding the pinhole god severely fucked up the world of iron lung) The soul, too, is somewhat ignorant to the world of Deltarune. The player canonically views this world through a rectangular, pixelated, strictly top-down perspective usually revolving around Kris (when we are in their body). It's only through this window (figuratively and literally bc computer windows haha) we get to interact with the universe, not to mention Kris's consistent tampering with what we do or see. The pinhole god and the soul are incredibly powerful beings, capable of twisting the universe until it breaks, and yet both are so woefully ignorant to the full picture of what's even happening. (I've seen some headcanons that the eye of the pinhole god could be symbolic of us the audience as well, which I fuck with)

(Attached to their human blorbo) This may be more conjecture, but I like the headcanon that the pinhole god has taken a liking to Simon in some twisted way. That it saw this struggling, crying man in the bottom of its blood ocean and went 'yeah okay I choose this one' and proceeded to tear him limb from limb, atom to atom, for its own curiosity and to fulfill their deal to keep Simon alive. I hope that we the soul in Deltarune don't have these feelings towards Kris the hapless human teenager, but given the infinite possible people playing, I wouldn't rule it out. Our perverse sentimentality(tm) as fans of a piece of media is a core theme in both Toby games, and like the pinhole god, we will dissect every character to enjoy them to the fullest, seeking them out in every possible scenario and condition, however horrifying it would be to the other side.

(Decides fate of said blorbo) I have been writing for way too long. Anyways lets keep this one short. Simon has no agency. Neither does Kris. Both of these characters are spun around by other in universe authorities (Carol, Dess maybe, Eden, the COI, Ava) they are indebted to (Kris's mysterious promise, notably). But also, to the red eldritch horror. Simon's life is put in the pinhole god's hands when he has no hope of going to the surface, Kris's life is constantly put in our hands when we are thrust into battle (or whenever gameplay happens, really). I believe that both the soul and the pinhole god are representative of the way these little blorbos are being stripped of their autonomy (one being bodily, and one being more about their lives in general) :D