[Challenge/Maze, Lunatic] The Coming of the Dark

In the desert if you meet ghosts instead of pyramid there should be a save point on the way back, in the screen x969y1006.

The way up in x999y1016 is too unclear.
The background is too dark in lava screens like that. It's very hard to distinguish background from walls.
Save point is needed at x1001y1017.
Screens x999y1020 - x997y1020 are very annoying.
Save point is needed after ninjas of x992y991.
In x990y990 there's no need for these random flying things. They aren't fun in any way.
You also overuse invisible spikes and other unexpected things.
Before you press the switch in the Beast Heart room you can climb up and get to wallswim.

I'm thinking specifically of the two points where you reach a keyhole-blocked dead end and find a key for a seperate area, then have to backtrack all the way to the hub.

blind trap-avoiding maze in the pyramid, and the bit with all the red flyers when leaving the castle

Inside the pyramid, just before the blind trap maze, you can climb up from the save point and wallswim up into the room with the water pit

x1001,y1018: having no idea where the spiky tombstones makes an otherwise challenging puzzle downright impossible on the first few runthroughs, and there's no save nearby.
x997,y1017: as far as I can tell, this jump is impossible unless you do the tricky put-the-umbrella-away-before-the-double-jump which is very difficult on my crappy 2-key rollover laptop keyboard.
x9991020-x997: Three screens with with the most erratic, unfair monsters, and no save points because apparently Talps hates his players. 
x971y1006: Three fires shooting at you from all sides, without any ability to dodge, and a hidden maze so you don't even know where you -can- dodge.
x971y1008-y1010: You complete a really difficult challenge avoiding 8 shooty fires, only to drop down into an instant-death screen with no way to save or avoid, except through trial and error.
x993y991-x991y990: The spike masher room is just... I mean look at it. There's no "safe zone" and I found myself believing it to be legitimately impossible the first two dozen times I did it. Plus I kept dying to the ninja-monkeys or the waterfall jump every other respawn which just made it extra frustrating, having no save right before the nigh-impossible sceen. Then you get through all that, only to die to some random erratic red guys just before you can save.
Finding the secret ending... never did. Even with the level editor, finding the way through that maze is borderline impossible.
Having to backtrack to each area 2-3 times with different items/keys to unlock doors.

-For one, it's great seeing this early level and knowing how far both Talps and the community standards in general have come in story, pacing, and level design between this and later levels.
-It's also interesting to see some of the things the community has lost over the years.
----It used to be a common trope to have the player go through screens normally and then get the eye and have a different set of challenges to overcome going the other way. I like that mechanic, and it's done particularly well here in the Mining Mountain section. Areas suddenly because much easier or much harder with/without the eye.
----Backtracking used to be much more common, and I think it's a mixed bag. Sometimes its fun to go through an area already completed with a new power and just kind of blow through the challenges like an acrobat goddess and other times it feels like a chore to have to redo something you've already completed. 
-I enjoyed the beehive quite a bit. One of the few beehives done well in various KS.
-Most of the areas actually were really fun. It's an enormous level, and the unfair areas were only a small percentage.
-The Heart of the Machine had appropriate difficulties in terms of challenges.

Search for one secret room in each zone. I'd say the most 'obvious' one is given away by one of the cats in the beehive.

x1001,y1018: having no idea where the spiky tombstones makes an otherwise challenging puzzle downright impossible on the first few runthroughs, and there's no save nearby.
Something you have to do is a designer is remember the player doesn't know everything you know. I hadn't figured this out when I made this screen.
x997,y1017: as far as I can tell, this jump is impossible unless you do the tricky put-the-umbrella-away-before-the-double-jump which is very difficult on my crappy 2-key rollover laptop keyboard.
Talps Productions accepts no liability for any injuries, stress or stress-related illness caused by the limitations of the player's selected hardware.
x9991020-x997: Three screens with with the most erratic, unfair monsters, and no save points because apparently Talps hates his players. 
To this day, I... I like the snowball monsters. Listen my friend; when you like an enemy, the appropriate thing to do is shove as many of them into a series of screens as you can without making the challenge actually impossible.
I should start a protest outside your zoo.
x971y1006: Three fires shooting at you from all sides, without any ability to dodge, and a hidden maze so you don't even know where you -can- dodge.
...Ok, yeah, fair enough.
x971y1008-y1010: You complete a really difficult challenge avoiding 8 shooty fires, only to drop down into an instant-death screen with no way to save or avoid, except through trial and error.
Cf. comment on first complaint.
x993y991-x991y990: The spike masher room is just... I mean look at it. There's no "safe zone" and I found myself believing it to be legitimately impossible the first two dozen times I did it. Plus I kept dying to the ninja-monkeys or the waterfall jump every other respawn which just made it extra frustrating, having no save right before the nigh-impossible sceen. Then you get through all that, only to die to some random erratic red guys just before you can save.
Another fun fact: when I navigated to this screen to check out what you were whining about* I started humming one of the KS default music tracks, and was pleasantly surprised to realise when I checked that I was actually unconsciously humming the music that plays in those screens! And that is all I have to say about that!
Finding the secret ending... never did. Even with the level editor, finding the way through that maze is borderline impossible.
DonDoli did not find the secret ending on his playthrough. But he did find the secret that signposts the secrets that lead to the secret ending!
Having to backtrack to each area 2-3 times with different items/keys to unlock doors.
But that's part of the fun! (Talps said as he shovelled money into a duffel bag, shortly before legging it towards the Mexican border.)

-For one, it's great seeing this early level and knowing how far both Talps and the community standards in general have come in story, pacing, and level design between this and later levels.
Well, at least I can be a bad example!
-It's also interesting to see some of the things the community has lost over the years.
----It used to be a common trope to have the player go through screens normally and then get the eye and have a different set of challenges to overcome going the other way. I like that mechanic, and it's done particularly well here in the Mining Mountain section. Areas suddenly because much easier or much harder with/without the eye.
----Backtracking used to be much more common, and I think it's a mixed bag. Sometimes its fun to go through an area already completed with a new power and just kind of blow through the challenges like an acrobat goddess and other times it feels like a chore to have to redo something you've already completed.
Both of these are features in 'The Machine' and 'A Strange Dream' so I think they carried over when a lot of players turned designer (and is similar to the reason why there are several levels about turning off machines. Ahem). That is definitely the right way to use the Eye in my opinion, but not at all the easiest thing to design. If I ever finish my latest project, you might appreciate my eye-section.
-I enjoyed the beehive quite a bit. One of the few beehives done well in various KS.
Thanks! As I recall, I was digging through the default tilesets (because there was no way I was gonna design my own. As if!) and I saw it and I thought, 'What if there was an area in my amazing first level where Juni inexplicably shrinks and goes inside a beehive?' True story! The next time a tileset inspired me to make an area in a level like that, the result was the entirety of 'Dragon Myth'.
-Most of the areas actually were really fun. It's an enormous level, and the unfair areas were only a small percentage.
How did you keep a straight face while typing that?
-The Heart of the Machine had appropriate difficulties in terms of challenges.
Ahh, I think what happened there was you typed 'appropriate difficulties' when you meant to type 'excruciating difficulties'.

The BEAST machine, like all complicated machines, was built by intelligent and thoughtful life forms. They were intelligent enough to create a machine of unimaginable power and complexity, one that could traverse space and terraform entire worlds, paving the way for future habitation by its builders. It would grow and adapt to new challenges, learning to navigate even the harshest environments. The builders were thoughtful enough to provide a failsafe; deep inside the BEAST's circuitry was a hardcoded directive, stating it must provide an accessible shutdown mechanism to allow sentient life to disable it. They never meant to terraform inhabited worlds, after all!

The builders miscalculated, a bit. Their short-lived minds, thinking in timescales of minutes or hours or years simply could not anticipate how the BEAST would evolve in its aeons-long journey across dozens of worlds. They never could have predicted that the cold, uncaring, algorithmic evolution would be guided more by its redundant layers of self-preservation directives than any of its other hardcoded goals. As it evolved to survive, the BEAST layered the failsafe mechanism in nearly impenetrable security measures. But a machine must obey its programming, and a hardcoded directive must be followed, and so the failsafe mechanism, however difficult to access, was still accessible.

The BEAST locked away its failsafe and hid the only access codes all across the planet. Sure, a driven individual could still access the codes, at least according to some models. Part of the code was hidden deep in the crust of the planet, far below the surface, near the molten mantle. Another was hidden in the last chamber at the very bottom of a long lost, ancient underwater temple. Still another was locked away and hidden at the heart of the strongest fortress ever constructed. The final piece of the code was hidden through anonymity: the BEAST selected at random one unimportant agriculture site among the many millions maintained by the planet population. Who would think to check there, in a beehive of all places, for access codes to the world-destroying terraforming machine?

This also explains why it keeps Juni's comrades alive as ghosts. It's not allowed to actually kill any sentient life, so it merely de-materializes them and keeps them "alive," suspended as ethereal holographic brainwave patterns.