Machine's Body?

[Alardem]

The story is weird and distorted, but I enjoy it for that. Just because things are left vague does not mean it's poorly written.

The last level is more representational than an actual segment of the Machine - recall that you transition into it by electrocuting the human heart powering the Tesla Tower and then having your vision fade white, indicating a hallucination. The body in the iron lung represents Mandus' ill condition, but judging from the Compound X canisters linked to it and his note about 'drowning being the kindest of suicides', I assume it meant he'd immersed himself in the compound and rendered himself semi-invincible.

When he sacrifices himself, Mandus perceives the action as having his heart ripped out. Again, I think this is more a memory than a literal representation. The way I see it, he'd ripped his heart out and used it to power the Machine and keep himself going. However, Mandus ends up reactivating the tesla coils and then delivering a terminal shock to the heart.

So the ending is really Mandus' memories going haywire as his heart is being destroyed, and the last thing he recalls is the process he went through in order to remove his heart in the first place.