I was going to reply sooner, but was delayed by school responsibilities. Anyways, I'll answer your questions briefly, though this is only from my experience and I might get certain things wrong here.

1a. Auto-clickers are either software-based (like AutoHotkey and other related software, which is the most popular option) or hardware-based (built into the mouse or externally configured by other peripherals, but rarely implemented). Generally, they are like the 'turbo' for mouse clicks.

1b. Some mice have a 'free-scrolling' feature that allows the player to spin the scroll wheel extremely fast to make fast inputs (i.e. the Logitech G502 Hero mouse and the Razer Basilisk V3 mouse, neither of which I own), which somewhat acts like auto-clicking but done manually. If the feature is completely allowed, it effectively makes the speedrun pay-to-win.

2a. Auto-clickers make shot spamming trivial, overshadowing various traditional mouse spamming techniques in terms of consistency and comfort (significantly less muscle stress since you can just press a button to spam shots for you). I say it is both accessibility-friendly and for ease of faster times.

2b. Auto-clickers are especially useful in boss sections and tank sections where it is faster to spam than not. 1-3 makes low 1:0x times easier (as low as a 1:03), the 2-1 tank can save around 0.7s when using an auto-clicker compared to none, 2-3 Buff Bryant can make yellows route somewhat viable again, and in 3-3, it can make the satellite phase 2 2-spin cycle much more consistent (but it doesn't speed up like in wide ammo runs when it goes straight to laser spins instead of waiting for satellite movements, and I wasn't able to do a 2-laser phase 1 with it which is usually seen in special ammo runs compared to the typical 3-laser phase 1 in normal ammo). Normal shootouts won't be affected that much due to the emphasis on accuracy and reloads anyways.

I personally think that we should not only worry about runs that use auto-clickers, but also runs that use macros. What if an entire speedrun is done not by a human, but by a meticulously crafted input recording of a perfect run (or a TAS)? Would we even notice it based on gameplay alone? Unless you have a few moderation tricks up your figurative sleeve, macros would make the entire speedrun extremely unfair and even create so much doubt in every run and player we encounter, innocent or not. That mere possibility is getting closer and closer as the days go by.

I obviously come off as pessimistic here, so I'll stop ranting here. Either way, I like to see new runs being submitted and players joining in mostly because there is not much active competition in the entire Time Crisis series nowadays. I suggest that any more discussions regarding this be moved to the TC discord server, as I don't check speedrun.com that often.

So far, there are no rules that strictly or explicitly prohibit the use of auto-clickers. I think it's difficult to tell apart gameplay that uses an auto-clicker from regular gameplay that just so happened to do frame-perfect spam shots (which is a 2-frame input window (5 frames if you count hit registers) in this 60-ish-fps game based on my testing in the current nightly build of PCSX2). It would be somewhat dumb to invalidate runs just because of this simple probable coincidence. I don't really know how we should handle auto-clicker gameplay. Maybe we would start using hand cameras or input displays. @matthewreality , what do you think about this?

So far there aren't any rules against using continues, especially with freeplay. Regardless, the current route is laid out such that continues are not necessary or used in any way (because it's slower to use continues). I'd say it's allowed for now just in case it can be abused to skip certain sections of the game or for practice reasons.

I was about to speedrun this game but I was kinda disappointed that Any% is literally NG+. I expected Any% to be something like unlocking all levels by earning stars from any of the levels and then finishing the run by completing King's Castle, but instead I just saw runners have all the levels unlocked and spam pause and next level to the end. That imo just ruins the actual challenge. (you can choose to separate Any% into NG and NG+) The closest thing to my proposed Any% is the All Levels category which I'm not really interested to speedrun.

That is way too much for me lol, possibly won't do it

The 'Invis glitch' you said is just the boost glitch but you do it during the Invis powerup.

My world record run of sub 2 gives you enough information of what perfect RNG would look like in a run. The powerups should be in this order: Invisibility (at 2500m), another Invisibility (from the range of 4500 and 5500m), Boost powerup (at 6500m or just before Invis slows you down but somehow I missed the pickup in that run), and another boost powerup (from the range of 8000 and 9000m.) I made heavy use of the boost glitch in that run (the part where i spam jump/slide during a boost until it runs out to conserve the speed from the boost). I would recommend spam sliding to maximize distance when you pick up your first and second Invis powerup. Then pick up the first and second boost powerups and repeat the boost glitch. When you survive after the second boost powerup, pull out your resurrection wings and die intentionally for full speed (do the boost glitch once more when the wings trigger) After the boost glitch, you should have a sub 2 minutes 10000m speedrun. I would call this the Invis strat since you would pick up 2 Invisibility powerups while doing the boost glitch. This might be, in theory, the fastest route for 10000m if done correctly. (The reason why I would not recommend having another Invis powerup as the third (and fourth) powerup is because you would slow down gradually to a point where you would match the default running speed or the game's intended boost end speed which is really slow.) (One more reason why I prefer doing the spam slide for the boost glitch for the 2 Invis powerups is because I think it would make the boost speed slow you down slower than spam jumping which I think conserves the most speed if the jumps are timed correctly but slows you down faster if mistimed.) I haven't really explored the true possibilities of the boost glitch, but so far, this strat is the only one I came up with, and it would be crazy if someone was to run through the entire level without any powerups but the conserved speed from the mega headstart. I hope this guide would help you. (also, Invis is short for Invisibility)

damn, wasn't used to having wanted stars in my casual playthrough

Maybe do a 5 stars speedrun instead? Sure it might be a little too quick, but it can be a valid category nonetheless.

or better yet, get 6 stars as fast as possible from a new and fresh game. That would be way better imo

In the meantime, download this 1.21.05 patch here: https://www.mediafire.com/file/15vdjty3c2uwtxc/nioh12105files.zip/file Update 1/26/2021: Santzo fixed the load remover to work with the latest version of the game (1.21.06), which means that you no longer have to download the patch above.

So here's the video of the glitch:

I found this glitch wherein during a speed boost (from wings, headstart, or powerup,) you keep jumping and sliding until the boost runs out and still keep the speed from the boost. Catching up with the conserved speed is hard tbh, but it can make a WR with a great time save. Should this be allowed?