You don't seem to be on the discord. I recommend joining it for questions like this. The link is below the name on the game, towards the top left of the screen near the cover art (I would post a link but I got banned when trying to do that before for something else so I have to explain where it is instead).

Anyway you're question. Yes the trick is frame perfect. You need to shoot the LETHAL homing launcher shot before the screen goes all black. The timing is random but Maurga uses an OBS setup to monitor the games audio to make it consistent. The link to his video showcasing it is below (it has no audio btw which is kinda ironic lol). As you can see he presses the shoot button when the grey bars vanish and before the screen goes black. Not much of a runner myself, but lemme know if you're still confused but I'd recommend asking on the discord to get faster responses.

Very famously on the Japanese version of the game you can clip through floors using the Arwing's landing feature. This was patched out of the USA and PAL versions of the game. And for a long time that was the whole story.

The way the glitch works is that the game picks a landing spot for the Arwing and the Arwing will just go to it while ignoring ALL collision checks in the process (I'll talk about the patch in non Japanese versions of the game in the next paragraph). The exploit happens because the game doesn't want the Arwing to abruptly change its movement direction or speed to get to where it needs to go, so it instead slowly transitions from its previous movement speed and direction for a tiny bit. This small amount of player agency is enough to clip through floors if we are boosting (aka increasing our speed) and facing the ground as the game lets us continue moving in that direction, even if the floor is in our way (remember no collision checks during landing). This means we go straight through the floor for a bit. Just let go of the landing button when fully clipped through and your out of bounds.

The Arwing landing clip was lazily patched in one specific case outside of the Japanese version of the game. The way the glitch was patched is seemingly with a small but effective raycast to check only the floor collision of the Arwing. The problem is that it is so small that if we hacked the speed of the Arwing to be faster we can clip through the floor again.

But what about non-floors. In theory we can go through walls and ceilings because ALL collision checks are disabled, and while I've had no success with walls, the ceilings of those looooooong tunnels in Mission 9 (Aparoid Homeworld) can be clipped through. Just boost while pointing it at the ceiling and hold land to land on the floor. Despite some slight changes compared with going though floors, it works the same, and we don't need to walk the whole way through the tunnel. Since the patch only checks for floor collisions, this works on all versions of the game.

I made a LOTAD (aka a very very low optimized TAS) to showcase this in a speedrun context and demonstrate that it is faster than the WR time. Current WR is 2:06 and this is 2:03. (Glitch is shown at 0:15 and 1:42).

The game makes it pretty clear that the Radar Jammers are only vulnerable to snipers. But the game lies and tries really hard to hide this. Once its eye is open ANYTHING can damage it. The only problem is opening its eye. You need to look at the Radar Jammer with the Sniper zoomed in at most two times to have it open its eyes. Once to get it to turn to you, and another to get it to fully open its eyes instead of squinting. To prevent the squinting you need to make sure you zoomed in with the sniper and looking at it when it starts opening its eye. Otherwise, if squinting, you can't damage it and you are wasting time. (I know Radar Jammers can look and attack you even without needed a Sniper Rifle but that isn't consistent and I don't know what causes it)

For any% speedruns this could help because snipers restrict all of your movement and being able to switch out the sniper and killing it with a different weapon could save some time. However this doesn't really work because of two things. Like I said before, to have it not squint you already need to be looking at it with a sniper rifle as it opens its eyes. Meaning that you're already looking at it with a sniper rifle meaning that shooting it doesn't take that much time even though you are delaying the time it takes to put the sniper away and being able to move again. The second reason is that nothing else can kill it in one shot. The Gatling Gun shoots fast enough with enough damage that you could strafe under a Radar Jammer while shooting it to save time. However, the weapon is very far out of the way, having the homing launcher (and possible other weapons) means extra weapon switches are required to get to it, its spray is really big meaning that it'll miss a lot of shots which is a big deal since the eye isn't open for too long, and you may not be able to walk diagonally when shooting it which is the fastest form of movement. So for any% speedruns, I don't see it being viable without further refinements.

I overlooked something though. Each hit to the Radar Jammer, lethal or not, with increase your hit and combo counter by 1. Meaning that using the machine gun on one cycle of the Radar Jammer opening its eyes could allow for an additional 15 points to the combo meter. The Radar Jammers have 1200 health (USA version at least) and the blaster does 20 damage while the machine gun does 15. Meaning that on 1 Radar Jammer we could get a 60 combo with the blaster, and an 80 combo with the machine gun. Assuming only the Blaster is used on all 12 Radar Jammers on gold difficulty, that's a 720 combo only from radar Jammers. This means a score of 9999 is theoretically possible. Although it will take a while. The video I have linked below is me getting a 60 combo with the blaster from 1 Radar Jammer in about a minute and a half.

Since we can farm points from one enemy, does that affect 100% speedruns? Not really. The requirement for gold in that mission is rather loose and literally skipping the first phase of the mission still makes it rather easy to get gold. The Japanese release has a 300 score increase (equivalent to 100 hit increase) so it might be helpful there if the machine gun is used on Radar Jammers, although more testing would have to be done before definitively saying anything.

Video of 60 combo with 1 Radar Jammer (I used single stick controls btw):

The gate in mission 3 is a rather flawed trigger. Mainly because it isn't one. If in Single Player on this specific map your position and angle are checked. If all pass you go through that special animation and land. The flaw is that it doesn't check any of these things when doing a barrel roll, a loop, or a U-turn. So by boosting and preforming a barrel roll at just the right time we can complete bypass the "trigger".

I discovered this recently on my own, but it was actually discovered ages ago. A YouTube video with an 8 month old comment on a YouTube video with this ID: plVtVPWBwGo was the earliest I thought it went. Apparently after asking the Japanese runner Maruga it seems to actually date back to March 17th 2005 on a Japanese site called "wazap". It was documented by someone named "techno" according to Google Translate (Can't put link here or post won't save).

Anyway this video will show this exploit in a practical sense to improve the speedrun for Mission 3 bronze. This is a LOTAD (exploit at 0:47):

Dying on the first frame of a mission phase starting leads to being able to skip it commonly done on missions 3 and 9. Some even did it on mission 2 with a frame perfect homing launcher shot. I just wanted to announce that it's also possible on mission 8.

The game considers you dead in the All-range mode Arwing when it explodes, not when it starts spinning out of control. So we need to explode the moment the final mission phase starts. Doing so requires:

1. Get health so low we die in one crash
2. Press down on the C-stick just before getting hit (timing varies depending on ?loading?)
3. Shoot the missile after crashing into it, or on the same frame (timing also varies depending on the same variable as before)
4. If you are frame perfect then done. You did it.

This works because as you are in the animation for doing a u-turn you won't enter the death state and can still shoot when your health is 0. Afterwards you'll have 3 seconds where you spin out. So if we delay our death perfectly, literally frame perfectly, you are able to die on the first frame of the final mission phase and skip it. Realistically not RTA viable outside of ILs, but its neat enough to share.

Edit: I forgot to mention that the cutscene that plays at the end of mission 8 will crash if the Arwing is destroyed because its in a state that's normally impossible. Skipping the cutscene bypasses this crash. I also forgot to say this works on all versions of the game, even PAL. It works on PAL unlike other missions because the patch involved making you invincible at the start of any mission phase which does nothing if your health is already at zero like it is here.

Showcase in a TAS video: