Thanks for answering the question about it being at least a little serious. Some more replies, then:
Vakama tells Tahu to use the Mask of Time only in an emergency. We do not know why the thousand years of being menaced by Rahi, and the month or so of organically controlled robots trying to render the island barren, do not count as emergencies.
First, there were no Toa over those thousand years, and Turaga can't use Legendary Masks. That said, even if they could have, I'd say we do indeed know why.
At least in hindsight we know that Teridax was purposefully only "menacing", not actually trying to conquer. And since 2004 in Time Trap, at least, we knew that part of it was in fact about the Vahi; Vakama threatened to destroy the mask if Makuta ever went for it. Vakama believed that the reason for the Rahi attacks being somewhat half-hearted was about this. It also seems that they did know Teridax was guarding the way back to Metru Nui too, so they believed that conquering the Matoran was not high on his priority list. Now we know that was in part because he needed the Toa to play along with the Plan; part of that required the Matoran to repair Metru Nui. Matoran wearing infected masks could do this, of course, but then the Toa would be less likely to play along.
Anyways, if you're asking why didn't Vakama give the mask to Tahu as a precaution for the battle against Teridax that brought the end to the Rahi attacks, the answer is that the Turaga didn't know if they could trust these Toa. They had, after all, personal reasons to not blindly trust Toa.
And the Bohrok were like the Borg -- in some situations, leave them alone, and they leave you alone. (But if you try to defend a plot of land they're trying to clean, then they get nasty.) Also, was there really a situation in either case where the Vahi would have even been useful? Slowing down the unlocking of a cage makes sense, but I'm not sure the previous two showdowns really fit that mask. But maybe if combining beams against the Bahrag hadn't worked Tahu might have tried it (although I forget now off the top of my head, if Vakama gave it to him before or after that battle... >_>).
Also, Vakama, a being with a lifespan of tens of thousands of years, gives a priceless and dangerous artifact to someone whom he has known for a few months at most.
Well, this is why he didn't give it to him to deal with the Rahi. But time doesn't really compare well like that. If you need somebody to prove that they can be trusted to ride an expensive bicycle, seeing them ride a few times to ensure they know how should be sufficient. Once you know how to ride a bike, generally it doesn't matter how much older you then get. Beating (or seeming to beat) the Makuta once was taken as strong evidence the Toa were trustworthy, and delaying out of stubbornness of age could be far riskier, since the mask does no actual good in Vakama's hands.
Also, this is the same guy who was apparently willing to actually destroy that artifact, unleashing time-chaos, so this isn't really a surprising move for him anyways.
The Mask of Light is not a legendary mask, so all the hype over it is totally undeserved.
Non sequitur; it does not follow that only Legendary Masks are valuable. This appears to be power level fallacy; the assumption that what or who wins in a battle depends simply on a simple linear spectrum of "power level", and more powerful equals win. Actually it's all about the circumstances and strengths versus weaknesses. In this case, the main enemy and his servants are beings of the Shadow Element, which is especially vulnerable to the Light element.
This particular Mask of Light, as well, has the added benefits of being charged with Toa Energy, so it could make an actual Toa of Light; normal Great Masks don't have that (not even Legendaries -- actually because of this alone it is far MORE valuable than Legendaries, since it isn't actually safe to use Legendaries anyways usually*), being the only one known to exist (though we could justifiably call this a problem -- it might be more realistic that they'd make many of them, but that's a whole 'nother discussion), and having some knowledge programmed into it that downloads into the Toa's mind to help him achieve victory. (Plus that poem etched on the inner side to help out a bit.)
*Although the Mask of Life, admittedly, could make a Toa if it wanted. But you wouldn't want to wear it!
I don't care how powerful it is; if a mask falls into lava it should be destroyed.
That lava's heat comes from the automated furnaces of Ta-Metru, then is pumped underground, under an ocean (cool water sinks, and would cool the seafloor, and likely affect the pipes), then up along the dome, to the center top, and then up even more through rock, then comes out the artificial volcano, and along a lava river, and when it reaches Ta-Koro it's even almost at the very END of the lava river! Really it's amazing it's still molten after all that opportunity for heat to gradually dissipate. No reason to assume the lava at that point would instantly melt every metallic object; many metals and other substances have very high melting points, including apparently the rock the lava was flowing over, etc.
Besides, to even get the lava up there in the first place you have to have at least one type of protodermis that isn't affected even at the most extreme side of the heat.
And masks and such are made of purified protodermis. We even see lavaboards being made of another type of protodermis (it's really the same substance, just somehow behaving differently to imitate different types of matter) and not melting at all. So purified protodermis could simply have that trait or close enough that it would have to stay in the lava a long time to melt. Which would make sense -- you wouldn't really want masks to be more like ice cubes, right?
Plus, it was encased in rock for part of the time it was in the lava, which took the brunt of the heat, and Takua quickly pulled it out.
BTW, what does "how powerful it is" have to do with it? A mask's power isn't going to be activated (other than the Ignika, or a slightly cracked Mask of Time and presumably Mask of Creation) unless it's on a Toa's face [or Turaga in case of Nobles] and they will it to be. And Light doesn't seem relevant to surviving lava. But powers can indeed help; those pipes for example might have a cold power (even the lava surfboard might possibly have an always-on one, but we don't know that). We do know that Ta-Matoran have an always-on heat resistance power. But this is presumably not the case for Kanohi.
If you're going to argue that protodermis is too powerful to be destroyed by lava, then no one in the Matoran Universe (say, Takua right here or Jaller in 2006) should be afraid to fall into lava, because they are all made of protodermis.
Here again, this is an odd take. Why would a mere power level even seem to apply in this case? Wouldn't it be more normal to expect people to argue about higher versus lower melting points than "powerful"? The material that industrial vats are made of, that contain molten metal, etc. in the real world aren't "more powerful" than other materials, they just have a higher melting point. Anywho, the real problem with this argument is it seems to assume that all protodermis is the same, but we know that's not at all the case. After all, rock and ice are both protodermis (in Metru Nui, not Mata Nui), and the ice will melt at room temperature while the rock will not. And the people have organic protodermis which is surely much more vulnerable than their metal components or masks.
How did anyone fall for Takua's attempt to turn Jaller into the Herald of the Seventh Toa when it clearly shone on him first?
Things like this happen in real life all the time. People aren't always paying Sherlock Holmes levels of attention to everything.
Turaga Vakama says that the seventh Toa "will bring light to the shadows and awaken Mata Nui". When the time actually comes to awaken Mata Nui in 2008, Takanuva does no such thing.
There was a genuine miscommunication on this one, in fact. The movie producers thought that the light shining through the Hau-shaped decoration around that giant door at the very end was Mata Nui awakening (according to people who have some sort of special feature, or so I heard back in the day... don't think I ever got to see that myself). Thankfully they kept this claim out of the movie itself and just left it implied that Mata Nui had just awoken, so the canon story could salvage this. (This created untold numbers of questions in S&T over the years as people soon foundd out that bit of their commentary didn't match the continuing story that said he was still asleep.)
Vakama's statement still works fine, as Takanuva did do the necessary work in opening back up the way for the Matoran to return to Metru Nui, which was one of the prerequisites for awakening Mata Nui. And we already knew that awakening Mata Nui was the Toa Mata's destiny, not Takanuva's, so virtually everybody has taken Vakama's statement as obviously intended in an indirect sense; that Takanuva would help the Toa Mata awaken him, which is indeed what happened (both here, helping them move toward that, and he actually fought alongside them in Karda Nui later).
But Rakhshhii is a right mess to spell.
Actually Rahkshi is one of the better ones. It has the "ah" sound, and actually uses "ah" in the spelling. And usually "i" is "ee" in Bionicle words. It's spelled just how it's pronounced.
Why does Makuta only create six Raakshi? As far as we know, there are no limits on his Kraata-creating powers.
Sure we know of limits; he can only make one Kraata at a time, and had very little time to do that, plus they have to "soak" a while (and he has to make six more Kraata to control the suits that the first six turn into). Of course, we could fault him for not thinking of the necessity at some point in those thousand years, but then again, we know now that he wasn't actually trying very hard to stop the good guys since he needed them for the Plan.
But we shouldn't really need to know of limits to accept that he only made six; that's an argument from ignorance fallacy. Only if we had positive knowledge that he didn't have any limits would this argument work, and it doesn't seem likely anyways that it would be unlimited.
Forget it, I have to include this sin from Mask of Light. Why in Bitil's (for lack of a better character) name does Kopaka perform his scan on the Ko-Koro gate? He knows the gate of his own village
That was just artistic license, but isn't really the problem here. As Greg might put it, in the "movie universe" that's just how the power would work automatically, and since he was using it to see if Ko-Koro had been attacked, it would display any information about what is in its field of vision. But canonically it does not seem to display information in a HUD type way anyways -- so the problem is that it is deviating from canon just to look cool, really. But canonically, he wouldn't fail to be able to read the gate. Basically, you're misinterpreting what he's looking for; he's trying to look inside the village to see whether it's been attacked, not trying to find out what the gate says.
Onua, who has control over Earth and is IN A MINE, is unable to stop the ceiling from collapsing on him, destroying his village and probably killing a few Matoran.
No real objection to most of this, but just for the record, no Matoran died on Mata Nui island except Jaller. I always thought that scene was odd too (though not odd when you consider these things were choices made by the movie people, not storyline experts lol). Although, he did want the Rahkshi stopped/slowed down, and that probably helped. It seems implied he then used his power over Earth to dig free.
While we're at it, what's the difference between the elements of Stone and Earth anyway?
To use Greg's stock answer, have somebody throw a clump of dirt at your head. Then a rock. Feel the difference?
(Do not try this at home. )
The more technical answer: Earth is loose particles smaller than grains of sand, stone is cemented material of generally the same type but with particles larger than sand (Sand is a separate element, albeit only an SM one). Earth will flow something like a liquid under the right conditions, while stone will not (not necessarily, anyways; pebbles could, but you could have a tall tower made of a single stone for example). Earth can also grow plants in it and so forth.
Why did Jaller and Takua need to travel through Ta-, Le-, Onu-, and Ko-Koro before getting to Kini-Nui, which is supposedly in the centre of the island? It should be right next to Ta-Koro, or what's left of it.
They were searching for a Seventh Toa, not making a journey to a set destination.
But why did Takua/Takanuva need to rename himself?
Set had to be marketed before movie was released, and calling it "Toa Takua" would have given the big spoiler away.
In-story, he didn't have to, but that's what I call Need Fallacy (applied in a somewhat unusual way, though). People do things both because they want to and need to, not just need. I guess he thought it was more fitting. We know that it basically means "new Takua" -- it was a poetic way of saying "I'm putting the old irresponsible me aside now -- the me that tried to deny my destiny and got my best friend killed because of it" etc.
Takua becoming Takanuva shows that you can wear one Kanohi on top of another. Why don't Toa do this? Double the powers!
The magnetic connection surely has limits, and there are other obvious problems. The same logic would lead to absurd results -- why not fifty masks sticking off your face so you could have fifty powers with no need for even one Suva?
He wasn't doing it to double powers; he was doing it to accept a transformation that removed the Matoran mask in the process. But we did see Vakama do this with the Vahi. So it is done, it's just that it should be temporary and it's best not to.
BTW, they still can only use one power at a time, but it does have a time advantage.
Also, this is basically what Golden Kanohi are.
We never saw what happened to Jaller's body, but if it wasn't destroyed (e.g. cremated by Tahu), there's a sin. When Takutanuva... revives Jaller, he says "that mask needs life". So the idea is that Jaller's essence left an imprint on the mask, and Takutanuva is using that to revive Jaller. But if Jaller's body wasn't destroyed, Takutanuva is teleporting Jaller's body from elsewhere and reviving it, making his statement false.
I'm not really following.. what statement is made false? And why? But we don't know exactly how it worked yet. We're still learning about the revival process in the LMB topic; new light has been shed on it recently. For example, we now know that the RS Bringup teleporter doesn't work on Mata Nui, so we can rule out that the old body was teleported up there. So, no second Jaller.
It sounds like you're assuming that if the old body wasn't destroyed, for some reason it absolutely had to be teleported there? Makuta does have a teleportation power, so that's one option, seemingly, but why would it be the only option? He could simply materialize a new body. That's what I always assumed was happening.
In the case of Takanuva's revival moments later that is probably what's happening; his dead body was probably still in the rubble, not teleported there in smashed form (ew... ) then put back together. On the other hand, that would mean the body was still there when the Piraka came to inspect the rubble, so still ew lol.
Makuta Teridax, the great and powerful supreme antagonist of all of Bionicle, has his armor crushed and is thus rendered mostly helpless until 2007...by a door.
Actually I thought that was one of the high points of Bionicle. Realistic antagonists make mistakes, even embarrassing ones. (Although the mistake was really the falling in the EP. We don't know that Makuta wasn't somehow subconsciously manipulating the fusion to fake a defeat there too. It certainly didn't actually harm him in any way injurious to the Plan. And Takanuva in fact speculates along these lines at one point.)
Takanuva's revival makes no sense. What power brought him back to life?
It was definitely bad that this wasn't explained, but it's pretty easy to deduce what the answer must be. Makuta, who obviously knows how to revive somebody, has been living next to that machine for a thousand years. Since that machine clearly has the power of revival (incidentally, why do you need to ask? You saw it in action, so you know the power...), it makes sense that his study of this while he was there led to his knowledge of how to do it by himself, and the fusion used that knowledge while it was unable to reach that device to revive Jaller.
Really Takanuva's revival is the one that makes more sense when you think about it; that machine actually naturally has the power (we just don't know who put it there or why, or why Vakama figured it out, but obvious possibilities to all of these can be theorized; Great Beings, another RS-like contingency, and visions or deduction or maybe ancient legends), but revival is not listed among Makuta powers. But the presence of this machine makes Jaller's revival end up making sense, because now we can understand that Makuta must have found out a way to imitate its effects.
Also, two revivals within two minutes of each other.
At first glance and from a superficial perspective yes, but considering the above, that's actually one of the strong points of the scene. The problem was how it was handled, as it's unrealistic that all the characters there would act just as they did. The Toa for example would realistically have had a conversation about what Vakama was deducing or remembering from a vision or whatever, rather than just lining up like paper cutout figures. But IMO it's mostly forgiveable, because it would be anticlimactic for the emotion of the movie scene to end a dramatic, emotional climax with "Wow, Vakama, what is this thing under the floor? How's it work? Why did the Great Beings make it? How did you figure it out?" and then get a series of answers. More realistic but nearly all modern television/movie climaxes avoid strict realism for emotionally uplifting finishes. (Kind of a pet peeve of mine, but you can get why they do it.)
Lhikan had information from Mata Nui, the most trustworthy of all, that these Matoran were the destined ones. I think his choice was justified.
Plus he would have had time to get to know them, though we don't know that he did. Anywho, there a legend about those Toa coming. I'm not sure how the Turaga knew about that, but Vakama's visions might be the answer. The Matoran clearly expected them. It wasn't like they just showed up as a total surprise.