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The central mechanic here is original and interesting; I just wish I could see more of it than you have finished already. I would encourage you to submit to various juried exhibitions more aggressively once the game is further along and you have a definite release date in mind.

I've no idea what the shield does (is it not implemented yet?) so you might clarify that for the player.

Another thing I would suggest is that you let the player know right away that the X button cancels. Right now you just say that C interacts, arrow keys move, Enter brings up the menu... so naturally what I did first was to hit Enter, hit C to look in inventory, have it tell me there were no items... and then had no way to get out (since neither Enter nor C nor Esc took me out of the menu at that point)! I did eventually figure out X by trial and error, but was frustrated that the game entered what was essentially a freeze state right at the very beginning.
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I'd like to preface my feedback by disclosing that I'm not entirely sure you're making a game that speaks to me. I am not a academic or a critic; I'm indifferent towards capital-A art games (I love Journey though, go figure). And the info I read in the description made my eyes kinda glaze over as effectively as when people start throwing around terms like "ludonarrative dissonance". You don't, but I feel like it's what you're hinting at in the description. So I came back to The Ocean several times, stepping away when I disengaged, and returning after I felt ready.

That said, I don't believe in ars gratia artis; I like creative works to have meaning. And I don't think I get the meaning behind Even the Ocean.

The Ocean is an ambitious undertaking, and I'm not sure that narrative connecting it to another as-yet-unfinished piece will enhance it further.

I'll discuss the aspects of The Ocean that I enjoyed before I enter into my criticism.

From the natural world to the industrial underground, The Ocean is drawn with stunning detail. The gorgeous tiled textures, from the rocky cliffs to the lush foliage to the captured fossils, from the metallic walkways to the glowing lasers to the energy blossoms make for an impressive environment I was keen to explore more than I was allowed.

With simple-to-understand, difficult-to-master mechanics, The Ocean possesses elegant systems design. The theme of balance is evident without being in-your-face. I had to thoughtfully parse every move I made. Even carefully considering how to proceed wasn't enough, as execution of my plans was another level of difficulty on top of the strategizing. The energy balance mechanic is evocative of the life bar in countless other games, and though some would call it derivative I think the execution is really fantastic and sets it apart enough.

The shield mechanics in The Ocean haven't been used often enough in the 20-some years since The Lost Vikings, and aren't used often enough here, either. I'd like to see it in action more, as it's a flexible tool for solving puzzling areas.

I also appreciated the spouting jellyfish-like creatures, though at times they weren't actually necessary when I could otherwise wall-jump. Another aspect I'd like to see more of in the full game.

However, the level design simply isn't as enjoyable in that less adept players might not be able to fully enjoy the visuals and mechanics while struggling through; it's not a pick-up-and-play game and requires a level of exactitude that can only be described as Nintendo Hard. One instance stands out: when taking the green squares to the red squares to turn the red circles green, the far left path took more than 20 excruciating tries before I lost count and even more before I decided enough was enough and moved on to explore something else.

And then there's the starfish.

Putting the uncannily-alike-textbook-renderings-of-the-female-reproductive-system entrances and tunnels--orifices?--to the starfish aside, the starfish makes as much logical sense as the Wind Fish atop Mount Tamaranch.

For all the talk of thematic consistency between two the parts--The Ocean, which I have before me, and still-in-development Even--this demo felt disconnected and disjointed, which I hope is only a result of its unfinished state. I couldn't elicit a link between the Gauntlet and Nature areas, the fearsome, futuristic, stress-inducing underground and the superficially calming yet beautifully sinister shore.

Which is why I'm skeptical of your contention that Even the Ocean is two thematically-linked games in one.

If it were as straightforward as the mechanics suggest, the Gauntlets as a standalone really appeal to me, in the same way VVVVV did. Y'all could really expand it, with boundless potential for creating puzzle-filled levels just like VVVVV. But instead it transitions into this other thing that I don't get.

This other part could also be another full-fledged game, I suppose. It requires more suspension of disbelief--it's a nonsensical environment even in the fantastical context of other aspects--and that'd be fine...on its own.

Again I'm hoping it all comes together.