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
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.
As against TPSD you cannot hit King Bulblin multiple times with a quickspin anymore. Jump attack him as soon as he starts his attack animation, then chain quickspins. After the 5th quickspin backhop to evade his attack and then finish him off in the same way.
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.
For the first phase sword slash to make the darknut block then slash him 5 times, then make him block again and do 6 slashes to knock off his armour. Now make him block and do 3 stabs, 3 stabs and the 4th combo then jump-attack and spin-attack. 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.
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.