I really enjoyed this game. Cool throwback vibes to early 3D platformers like Super Mario 64 and a good challenge with both hidden collectables and end-of-level rankings. Now you have built the engine, will you be making more levels?

control is very bad

Oh my god, the camera controls are awful. Just because you like controllers isn't a good reason to make it nigh-unplayable on keyboard. Simply having the camera follow the mouse like in an FPS is standard and easy to implement

i see this game is the "speedrun" kind of game so i'm definitely not the target audience for it, but i gotta say the wall jump mechanic is super aggravating.

i'm not sure if it's because the camera moves as you're performing jumps, or adding directional influence mid-jump changes your trajectory, or because it takes a while for the wall slide to register, but i can't count how many times i had to climb the mountain in the middle of the map over and over again, because either i didn't climb on the right surface, or i landed on the wall to the side instead of the one opposite of where i'm jumping from, or i simply didn't stick to the wall and just slid off.
eventually i simply stopped inputting anything else and just kept mashing spacebar between walls, hoping the auto-camera was designed to make those jumps as easy as possible to land, and somehow made it to the top.

minor annoyance is also how diving from mid-air has immense endlag and covers extra distance as you land, with seemingly no control until the entire dive animation ends.
i kept trying to dive after accidentally missing a jump to hopefully recover, and instead ended up throwing myself off cliffs, resulting in a worse position than i would have been in, had i done nothing at all.
though i suppose this part is intended.

tl;dr sticky wall jump is rough. everything else seems fine? to an extent;
though i'm not sure if it works for speedrunning purposes.

EDIT: i don't know what you changed specifically but it feels so much better to play already.
i definitely noticed the change with the dive end animation because i could actually use it to platform instead of a hailmerry.

i didn't realize how much i needed mouse controls for the camera until i had it; it makes walking around so much better because turning the camera as i'm walking now feels seamless, instead of doing hard turns which would mess around with my character orientation.
as i keep holding the same key while moving, turning around the camera at a sharp angle with keys tends to make the character spin around in place instead of going in the same direction, so it's definitely a welcome change.

i don't think there's necessarily been a change with the wall climbing/jumping (which was my personal bane) but for some reason it doesn't feel as unwieldy as before, so it must have been a combination of the camera control change, plus being able to dive with purpose.
even manage to get past the mountain in less than 10 minutes this time, so that's a result.
i wouldn't say it's "good", but it's definitely better than before.
i mean the wall-jump, specifically. the game is good

also, idk if this is just me being bad, but sometimes the jump height feels just a bit too low compared to the platforms?
basically, you can do a full hop to get on top of a platform, but more often than not i end up barely sliding onto its surface just below the top rim of the platform, so i end up stuck in a wall-jumping loop trying to simply jump and land on top of a platform more times than i would like to admit

An enjoyable little game.
Not sure why, but nostalgic feelings of "Croc: Legend of the Gobbos" were awakened in my mind. Probably due to the gems, even though the way to aquire them has no similarity whatsoever.... And the gems themselves don't even look like the ones from Croc. lol.)

Onwards to the technical stuff.

Not overly hard, yet also not overly easy. (Although the enemies seem to serve pretty much no purpose at all. Took a few hits on my first round, but health seemd to refill without me noticing, thus also rendering the heart pickups kinda redundant. Doing a quick check now, before writing this, it seems health is also refilled per 5 coins collected.)

A few of the jumps on the way up the center plateau were a bit tricky at first, mainly due to it being a bit tricky to gauge depth perception. That final bee-jump in particular. Always felt like I'd overshoot it, so I held back and fell short on the jump. Of course, when I did try to compensate this, I usually overshot it, resulting in falling down (and with some luck, occasionally landing on the retracting platform directly below).

Assuming starting position has you face north, the star due west of the center plateau, the one on the cloud, was a bit tricky too. Jumping from the final cloud was a bit odd.
Tried slide-jumping, but the the cloud I was standing on didn't allow for a good slide. (Some strange inertia going on. Probably due to it being a moving platform.)
Tried a regular jump.... Obviously fell short.
Tried jumping, then diving.... This was the solution that ultimately worked for me, though most times I'd hit the edge of the cloud and start wall-sliding.
....which brings me to another point; The ledges in the pits in the area leading up to the cloud-star.
While the player character is perfectly capable of jumping high enough to climb these ledges, it is only juuuuust enough to manage to do so. There are inconsistencies in being able to do so though; If you are holding [forward] (any direction, so long as you're facing the ledge you wanna jump on top of), you'll be very likely to start wall-sliding on the edge if the ledge. (There seems to be a slight slipe to the ledge-edges... This might be a contributing element to this issue.) This could probably be resolved by altering the terrain just a few pixels in height, so as to have the player character be able to clear the jump with sufficient margin. (Mainly an issue in the above-mentioned pits. The jumps leading up to the center plateau didn't cause such issues.)
The one pit where 1 cloud moves underneath some wooden beams wasn't all that much of an obstacle, though at one point I got a bit curious.... So I stood my ground instead of jumping over the obstacle. Result: I simply wound up clipping through the first beam.

Controls

While I'm fine with using WASD for movement, IJKL for camera just feels.... weird.
Arrow keys for camera would've been a better option. (Personal opinion.)
Optionally, arrow keys for movement and WASD for camera would also be perfectly fine. (Personal opinion + grew up with PC gaming, and have used both of the above layouts.)
I did try using the mouse for camera movement, though having to click the RMB to enable camera movement was very impractical. The movement sensitivity was way too low for this to be practical at all, requiring a release of RMB to reposition the cursor in order to further aim the camera in a more desirable direction. And if the (now invisible) cursor were to move outside the games frame (even though "captured by the game"), it would result in Rick-Clicking outside the game, thus losing focus of the game (and auto-pausing as a result of this.... which is expected behaviour and not much of an issue in itself).
The inputs to re-center the camera are a bit borky too. They work fine if you're standing still when using them, but if you are currently traveling in a direction other than directly forward, relative to the camera, then re-centering will attempt to reset to directly behind the player character, who in turn will alter their movement direction relative to camera angle, which in turn will make the camera re-centering overcompensate as a result of this. More often than not, I found myself completely turned around, wondering which direction I was actually traveling after trying to reset the camera.
Other than that, I appreciate that you included options to invert camera controls. For 3rd person view, my brain's logic center alligns with what "non-inverted" originally was; "Press [camera-left] to move the camera leftwards, thus looking to the right", or "Press [camera-forward/up] to move camera upwards, thus looking down". (Basically, treating the camera inputs as a secondary character input.) What is now considered "standard" is what oldschool "inverted" was. ^^
Other than this, the controls were perfectly fine. General movement inputs were nice and smooth. Although having both hands on the keyboard did mess a bit with my own mental wiring, making the simple task of pressing [shift] a bit odd, for some reason.... Not sure why, but I found myself having to think before every slide-jump. (Not important, but one specifi action is not accounted for in the game's instructions: Pressing [shift] while standing still results in a punch.... which amusingly sends the enemies flying through the terrain (clips through) and into oblivion.)
The auto-poisition of the camera was also well configured, moving to a favourable angle wherever relevant, albeit a wee bit bothersome when moving around on ground level in front of the center plateau, where it would constantly allign with the ledges leading up to it, even if one didn't intend to climb them at the moment.

NOTE FOR PEOPLE PLAYING: SPOILER ALERT BELOW THIS LINE!!!

The "game clear"
Took me a few tries, but I did eventually manage to bring my time down enough to get the final gem. It isn't an overly large map, but a bit of route planning was required.
Going for the cloud first was definitely a good call, as I could Slide-Jump-Dive (SJD) directly to the final bee of the center, climb that last part, then basically SJD straight to the top of the walljump area, from where it was no more than a simple drop to land on the final star.
This alone wasn't enough to bring the time down though, so a bit more trickery wound up being required.
For the cloud-pits, I found that I could simply SJD them entirely, skipping the time required to wait for the clouds to move across. (Still took my time with the final pit though, as the target ledge was at a higher altitude.)
Every retry was a bit tedious, as once the game was cleared, it remained on the "game clear" screen, and no inputs seemed to do anything at all, forcing a page refresh (or using the collapse/expand button above the game).
Ultimately, I managed to bring my time down to 01:30.42, though for whatever reason, the scoreboard did not update to reflect this.
It did grant me the final gem, at least, which prompted the "game clear"-message that "Dev comments are now available".
Reloading the game again (as there was no other option available), I went looking through the menu, tried "talking" to the bee showcasing the gems, and looked around everywhere else in the game. But nowhere could I find any trace of this "reward".

Minor potential exploit
After a walljump, hold directional input towards the wall you just jumped from, then dive back onto it. It may be a bit tricky (mainly due to camera allignment), but pulling this off well enough, you can climb any sheer wall in the game.
Doesn't hold much worth beyond exploration though, as it is way slower than using the intended methods, given the tight inputs required to pull it off and the likelyhood of messing up. (With TAS-level performance, one could probably insta-climb to the top of any wall though.)