Why would Goku be screwed if Freeza was only using half of his power? Because if so, Freeza could easily increase his power even more and prevent from being killed or fatally injured. The Kaioken x20 KMHMH was something set up to kill/injury someone at Freeza's 50% power, but if this latter can quickly increase it, then the attack is rendered useless. That's why Goku is hoping Freeza wouldn't just be using 50% of his power and rather, his full power.
Because that's still 50% more power he'd have to worry about in case the attack succeeded in seriously damaging Freeza. Goku was able to make Cell lose a lot of Chi by making him regenerate, but Cell's remaining power that he had yet to use would've still been more than enough to beat Goku at full-power. If Freeza is near his max and takes serious damage from the attack, that at least leaves them with an opportunity to deal with a significantly weaker Freeza. If Freeza is only using 50% of his power, then the damage likely won't matter because Freeza would just kill them with all of the power he had remaining.
The emphasis isn't exactly on how strong 50% Freeza actually was, but is on the validity of his clains (that being, using just half power).
That's not enough to differentiate my point, though. Goku's confirming that Freeza's only using 50% of his power. There's no reason for that statement to be made if Freeza clearly wasn't using that amount. It'd make more sense for him to say, "Wait. His power is even greater!" or for someone on the sidelines to say it. No one said anything.
If the idea Goku really wanted to pass was that Freeza 50% was stronger than he thought, then there would be no point in affirming Freeza isn't bluffing.
There is a point when 50% Freeza had yet to show how strong he really was. Besides pummeling Goku and slicing the planet with his attack, he was still holding-back a good bit at that level. Blocking the KMHMH only required him to use more effort, not more power.
The emphasis is all about on how Freeza was telling the truth as to be using 1/2
Then that means Freeza remained at 50% power because he didn't speak of Freeza being any different. His KMHMH being blocked merely proved without a doubt that Freeza was only using 50% of his power. Freeza's not telling the truth if he's using more than 50% of his power when he was kicking Goku's ass at 50%. That alone would render Goku's statement entirely useless for no particular reason.
and I don't see how he'd conclude it wasn't a bluff if Freeza stayed at 50%.
I do. By Freeza using all of his effort to stop the attack. Maybe that explanation doesn't work for you. That's cool. I think it's valid enough to compliment Goku's understanding that Freeza was using 50%, as well as Krillin's surprise at 50% Freeza not taking damage based on what he saw. Both of those statements tell me his power didn't change. When Freeza's power changes, it's usually noted. I don't see why that wouldn't apply here if he went beyond 50% of his power.
If Freeza stayed at the same power, then what he said about being at 50% could very well be a bluff, right?
Nope. Goku saw Freeza raise his effort enough to stop the KMHMH. That alone convinced Goku what it was. And you don't need to raise your power to put forth more effort because we know 50% Freeza was enjoying what he was doing to Goku without any visible strain.
I don't see how it means it. It means he is using 50%, but nothing more than that.
That's what I've been saying from the jump. If he's using 50%, it means he's using 50%.
If Freeza just uses 50% and doesn't show any signal that he could increase it even more, then Goku could very well be thinking he is bluffing about the 50% part and is in reality using all of his powers.
That's called wishful thinking, actually. The image I posted clearly shows Goku is hoping that it's BS.
If Freeza increases it, then Goku will know "so the power he was using really wasn't his full, so it must in fact be 50%, like he said".
If Freeza increased it, then Goku would've never said he was using half of his power. He would've said he was using more than that. Goku can sense Chi well enough. If there was noticeable difference between Freeza using half of his power when he was kicking Goku's ass and Freeza using more than half of his power blocking his KMHMH, it would've most likely been noted.
Way I see it, Freeza got serious and raised his effort at half-power to stop the attack altogether. A phantom power increase noted by no one isn't really necessary here. I get that most of you believe Goku wouldn't reach this conclusion unless Freeza's power went up, but I simply don't see it that way. Freeza's power going up wouldn't confirm anything other than he can raise his power. Goku confirmed that Freeza was only using a certain amount of power after he stopped it. Freeza should be no higher than 50% right there.