Are you saying the kicks were underwhelming? If so how can they be improved?
Yes, to me (and bear in mind that I am expert in nothing, just a student, OK?) the kicks were slow, telegraphed, underpowered, and delivered incorrectly. But as I also said, I don't know your style, so maybe that's how your style does it. I don't know your instructor or what you've been taught. My best advice would be to do what your sensei tells you to do and ignore what anyone else tells you, including me.
If you want to know how *I* would deliver such a kick, I can break it down for you. First, I don't do those kicks! Some of our younger guys do, but I don't typically practice them.
In the kind of kick you were doing, you want to keep your eye on the target to the extent possible. You turned your head away and never looked at the target again. An opponent would simply step back out of kicking range, or step to the side and wait for you to deliver to the target that was no longer there, then blast you from behind. You threw your hands around to assist your body turning, but without using them either defensively or offensively; they were simply counter balancing your body. That creates openings for your opponent and fails to defend your head at the same time. Your foot was facing up, you delivered the kick with the side of your heel. Some styles do it this way, so it's hard for me to criticize it, but I would not deliver the kick this way. I'd turn the foot (in this case towards the camera) and deliver with the heel as if it was a sideways ax kick. This also allows you to use the lever action of the knee to provide more power. What you have is a club. Clubs can hurt, and they can move things, but they don't typically create the kind of fight-ending damage you're looking for. Your landing was also off-balance, you staggered around for a second to get your footing. If you had missed with the kick, you would have fallen down. If you didn't fall down, if your opponent had simply stepped outside your kicking range when he saw you wind up, he would have made you fall down at that point.
Here is an example of what I am talking about. This is not me, I can't kick this high or this pretty. I am also not a TKD stylist, as this gentleman apparently is. However, to my mind, his form is excellent. Eyes on target (look closely you will see), hands in defensive position, heel properly aligned to target, balance strong (when you only have one leg to balance on, you want a good one-point).