If you have bombs you can kill all the bokoblins in one bomb. After Entering Hyrule Castle roll 11 times towards the trigger and then pull out a bomb before the cutscene starts, once you gain control pick up the bomb and avoid the swing from the first bokoblins and then walk back towards them all. It will then explode and kill them all
If You collect a rupee when charging a jumpstrike or during a jumpstrike you will delay the text until you land (If during charge up you will auto jumpstrike), Furthermore it is also disables all triggers as the rupee text is queued up next.
To do the skip first make sure you can get yellow rupee text. Break the box in the left corner at the main doors and boomerang the rupee and then target above to delay the rupee to have time to roll, while the rupee is coming to you roll to the very edge of the barrier 1 trigger (use the corner as a visual que) and then start charging a jumpstrike, the rupee will hit you and you will auto jumpstrike over the trigger allowing you to skip it. You will have to savewarp after King Bulblin 4
This saves minimal time and is not recommended for RTA. Get on the wall on the left side of the castle and pull out the boomerang. Aim above the rectangular hedge and throw the boomerang. As it is coming back to you, do a Long Jump Attack to get on top of the hedge. From here you can simply open the door to the next area and avoid the barrier/cutscene trigger.
From the main entrance to the Hyrule Castle courtyard, head over to the left (GCN). Stand near the bush wall, and lure a Kargaroc to come near you. Use an attack to knock the Kargaroc on the other side of the bush wall, and target him with an area attack. Back up a bit, and use the the area attack to super jump over the bush wall and past the barrier.
Simply roll into the trigger hugging the fence on your right, skip the cutscene immediately and then hold down-right and roll, you will be outside the barrier. On the way back you can just walk inside the barrier wall as it is only one sided.
After entering the barrier, enter the cutscene, immediately skip it and wait for King Bulblin to go into his attacking animation. Jump attack and chain 4 Quickspins.
After that backhop to evade his swing and immediately jump attack and quick spin him again to finish him off.
After King Bulblin is defeated there is a one frame window to backhop before Midna pops up. Press start during the backhop before landing and savewarp.
Alternatively you can use Iron Boots instead of a Backhop. Savewarp before Links touches the ground again.
This saves ~3 seconds over the usual route.
Simply Jump-attack towards the pillar on the right and mash pause and hold right. You will skip the cutscene as soon as possible and because link is in the air he will not walk into the barrier and holding right will keep you outside.
In the first room of Hyrule Castle, head to the middle of the room to cause the barrier to form. Head over to the right side (GCN) and wait for the group of bokoblins to appear. Just as they enter the barrier, hit the first one with a shield attack and use the helm splitter to jump over the barrier.
It is possible by standing on the very edge of the railing to clawshot the chandelier without needing to clawshot the closer one first, this is very hard to do fast as you have to be right on the edge and not recommended
If You collect a rupee when charging a jumpstrike or during a jumpstrike you will delay the text until you land (If during charge up you will auto jumpstrike), Furthermore it is also disables all triggers as the rupee text is queued up next. First Roll Right and break the armour in the way and destroy the other armour to spawn the blue rupee. Now Stand on the end of the trigger using the pattern on the floor as a visual que, target the blue rupee and then target where shown in the video to make sure the boomerang will hit you. Before you send the boomerang away line up with wall and target after the throw so you can start charging your jumpstrike in the right direction. If done right you can now skip the darknut, the side effects are that the darknut will sometimes teleport towards you and the music won't stop until you exit the castle.
For the first phase sword roll towards him, rollstab and then slash him 4 times, then make him block again and do 6 slashes to knock off his armour. Now run into him to block the sword, wait for him to pull out his second sword and slash him twice. Now use B&C to finish him off with 3 hits. To get the perfect boomerang angle stand inside the diamond and aim towards the pillar, when camera pans back just throw the boomerang and it will hit the torch.
Once you skip the cutscene pull out a bomb and run towards the Dynalfos, when they notice you stutter for a while and then throw the bomb at them. They will run away from the bomb when it's all the florr after a while hence why you wait for a bit.
Alternatively you can do a much safer and consistent strat which is barely slower.
Therefore just lure them to you and pull a bomb as soon as they start running towards you. When they are close, slash the bomb.
Before getting to the Small Key chest you have to fight Aeralfos. The fastest way to do this includes using the Ball&Chain.
Enter the Barrier and skip the cutscene as soon as possible. Hold L and mash the Boomerang button to make Aeralfos shield and instantly clawshot him down.
While the clawshot is in the air, equip B&C over the boomerang and swing it. After you hit Arealfos 5 times, throw it in his direction - it will kill Aeralfos on its way back if done correctly.
As long as you don't stand on unstable blocks for too long you can just cut right across the room. To do this roll across and show in the video making sure you go diagonally so you don't stay on unstable blocks.
This only works for the last group of Lizafos as they are closer together than the group below. Before spawning the barrier simply bomb-arrow the wall next to the right Lizafos and it will kill both of them making the barrier disappear before you watched the cutscene to spawn it. This can be used in All Dungeons and 100%
It is possible to skip the final Darknut fight by clawshotting the lantern right next to the boss door in Hyrule Castle. Get off the spinner early and position yourself carefully right before the barrier trigger. Clawshot the lantern and open the door.