Locked and unlocked Music Room from Double Dealing Character in the trials (left side) and full versions (right side). Versions B were used for the screenshots, due to larger window size.

seen from United States
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Locked and unlocked Music Room from Double Dealing Character in the trials (left side) and full versions (right side). Versions B were used for the screenshots, due to larger window size.
As you can see, at the bottom of the readme file from ver. 0.01a, the release date is 2011/03/13, but that’s not right because Double Dealing Character was released in 2013 (the correct date is showed at the beginning of the file: 2013/05/26).
2011/03/13 is actually the date when Ten Desires trial was supposed to be released first (but it got rescheduled). Probably ZUN just copied the readme.txt and modified some parts to fit DDC, but forgot to change that part.
The error was corrected in the readme file of ver. 0.01b.
The last sentence from Reimu’s description in the omake.txt of the full versions of Double Dealing Character has “.....” at the end. It did not have the ellipsis in the trial versions.
The last two rows from Wakasagihime’s description from the omake.txt of the trial versions of Double Dealing Character were modified.
trial: そんな彼女が何故か下克上を企んだようだ。 どういった心境の変化だろうか?
full: 打ち出の小槌の魔力に冒され、強気になっていたところ霊夢達に 成敗された。
今はもう大人しい。
Kagerou Imaizumi’s theme description from Double Dealing Character is slightly modified in the full version than in the trial. A symbol was replaced with a number.
trial: まあ三面ですしね。
full: まあ3面ですしね。
Stage 2 theme description from Double Dealing Character is slightly modified in the full version than in the trial. A symbol was replaced with a number.
trial: 一面ののほほん感とはうって変わって中二っぽい
full: 1面ののほほん感とはうって変わって中二っぽい
Stage Clear message was different in ver. 0.01a than in ver. 0.01b of Double Dealing Character.
In the manual of Double Dealing Character trial version, it was specified wrongly that you got 2 bomb pieces if you didn’t get hit while Sakuya A bomb was activated. It was corrected in the full version to 3 pieces.