Maybe you don't have the original source for this anymore, but typos:
"still appy" (in the OP) still apply
"familiaritze" (in the OP)
"The more the community grow" grew
"the genre your working in" you're
"Creative expression had become a matter of being judged by your peers (if the peers even took an interest at all.)" put period outside the parens
"There is no a doubt in my mind" There is not a doubt
"as a cover to cleverly hide the fact the true nature of the game and the ultimate objective"
"Will they actually be immediately piece together the truth from just that?" Will they actually be able to immediately piece together the truth from just that?
"rethink how to help the players progress" You can possibly read this in a different way that isn't a typo. However, I think since the start of the paragraph starts with "player" (singular), this reads as a typo of "rethink how to help the player's progress". This changes the meaning of 'progress' from verb to noun.
"reply to a blue truth that has unanswered question" reply to a blue truth that has an unanswered question
"upmost respect" utmost respect
"Strings that utilize strings" No shit.
"The string obviously then through the keyhole in the door" ???
"If it’s impossible to do, it may be worth to consider" worth it to consider
"How does the detective not notice the key being placed in the pocket?" has some extra spacing before the line
also, this kind of formatting with examples is very likely to create confusion in which example refers to what thing:
This is an example of (whatever).
Is Example A the example? Or is Example B the example? It's easy to lose track.
The early part of this guide was part of why I felt more confident writing despite having only reading experience. Though the Umineko-focused aspect probably applies less now, if that's the thing that would be 'outdated'.
Although there were Umineko-themed mysteries that introduced a new premise, it is more common for mysteries with totally original premises to appear now, which are not as limited in scope as locked rooms and may not even involve death. Original premises often create original tricks as well.