Of course, this would again all be academic if Battler had actually spent more time detectiving and piecing everything together instead of whining.

The game terms changed as soon as Ange put her grain of salt in that stalemate that lasted for 3 games already. Because of that, while they managed to force Beatrice to poke on Battler’s theories for this Episode, he is basically forced to elaborate a proper theory this time, instead of putting “what if” without really converging everything to a single direction (so far, he was only trying to remove suspicion regarding a certain character, or “the witch did that!”).

Before Episode 4, it was basically an endurance contest for Battler, in order to see how long he will last before surrendering. Because of that, the game was rather one sided, which was worsened by the magic show starting from Episode 2. Which is the reason why Ange intervened: Battler wasn’t going all serious (due to being torned that one of the 18 could be the culprit etc): instead of trying to win, Battler was instead trying “not to lose”, which is the reason why he is stuck in the meta world, instead of plain “you win / you lose” result.

The idea isn’t that Battler needs a scenario against Beatrice. Instead, he is totally convinced it cannot be magic, but because of his lack of information and sturbborn personality, he is going nowhere without a specific scenario. However, now that Beatrice forced him to consider one of the 18, it allows him to finally broad his mind (though because of the Kinzo’s theory, he is back to square 1, ironically).

But indeed, it wasn’t about the need to have a perfect truth applicable for all episodes. But that is absolutely not the point Ange is looking for: the game has to finish right now, for both’s sake.

To begin with, there was no true goal between Beato and Battler before that point, aside of their respective stance. Due to this, unless someone has the upper hand with solid facts, none can win.
By this definition, Battler had the burden of proof regarding the mysteries behind the murders occuring in Rokkenjima. Even though he “can’t” do that perfectly, so long he has the will to consider a human culprit, the game goes on. This is the main reason why Episode 2, 3 and 4 could occur even though Battler didn’t explain Episode 1 and so forth.

Now, due to the blue truth rule, the problem is like this: Battler “has” to adopt a theory that can work without contradicting any red truth. Because of this, it will force a red truth that wouldn’t be called otherwise (as if it was a random theory by Battler, it would be Beato’s disadvantage to take it down with an unecessary red that would simply give more hint, which is basically against Beato’s goal).
The problem with the blue truth is again the burden of proof, which is even more pressed in this game: the problem is that the anime basically skipped the explanations behind it: Battler has to explain EVERYTHING at the end of the game, with a blue truth that cannot be countered by the red. Should he fail to miss 1 thing, he lose, plain and simple.

Many of the previous arguments were unanswered by the red, which were basically on the “unknown” status: were they true? were they wrong? Before that point, it wasn’t possible to figure about them (example: what really happened in Episode 3 first twilight)
Now, there is a direct confrontation, which is totally different prior this point.

Now the thing is that even though the blue truth is an invaluable weapon for Battler, it is also a double edged sword, because unlike his usual “red request”, Battler has to conform with everything said in red before and those that are susceptible to be said later on. Because of this, a single mistake can just be his own demise.

Although Beato must counter the blue with the red, if Battler can’t explain everything with his blue, he is pretty much toasted.

Beatrice no longer wants to use the Red Truth the way she’s been doing it anymore because she’s bored with that rule. Also, to make matters more clear, Battler always asking Beatrice to repeat things in read is essentially him acknowledging Beatrice as a witch.

So, Beatrice gives him the power to use Blue Truth.

The Blue Truth is true until disproven by the Red Truth. So now, Battler has to come up with as many Blue Truths as possible to form a sort of wall, and then throw it all at Beatrice’s face. Beatrice will now only use the Red Truth as a trump card to break down this wall, which means Battler will have to be prepared for any counterstatement she may make and reinforce his wall with even more Blue Truths to use just in case. If Battler is able to use his wall to back Beatrice into a corner, Battler wins. If Beatrice is able to completely dismantle his wall with the Red Truth, Beatrice wins.

You see, the rules have changed so that Battler is no longer running in circles. Now that Battler has a shotgun to counter Beatrice’s sword, he too has his own weapon to fight on even grounds with Beatrice, thus actually giving him a chance to win.

One thing to note is that this is only the first DVD, which only covered the first two episodes, which were probably the worst two episodes in the entire anime thus far. I would not be surprised if the sales picked up when the more “interesting” episodes are released, or even when the series finishes airing and some of the anime-only fans actually start making sense of things.

That all said, if there was a second season it probably wouldn’t be out for at least 2 years, maybe even 3 depending on how many episodes the chiru VN series will have. So it’s not really something anyone can predict at this point.