All four are Touhou Stus.

http://www.fanfiction.net/s/7452541/1/perfectcovertfantasy - Rated T

First off, the fic contains many, many lines of unattributed dialogue in conversations of three or more characters. The fic generally has some problems with english syntax, and also introduces many uncanon elements, and has a gary stu.

http://www.fanfiction.net/s/7446979/1/AnEpicFailureoftheTouhouProject - Rated T

Countless many POV shifts, time and space jumps, and several syntax errors on top of that. It also features a gangster stu who was created in an uncanon manner, and gets special treatment from the OOC canons

http://www.fanfiction.net/s/7523377/1/TravelingfromDreamstoReality - Rated T

Author's note explicitly states that the gary stu is the author. Said gary stu, despite supposedly being a normal american teen, has learned magic without any help, and is basically the chosen one.

http://www.fanfiction.net/s/6869486/1/StrifeofVampire - Rated T

Gary stu turns into a vampire, rescues two very powerful canons who have been turned into wimps, taking down a huge amount of US military forces in the process. He also forgets who he is, gets a copy of a canon character's powers, then trivializes rape, incest, and pedophilia all in the same sentence for the purpose of woobification, while participating in the latter two with the same character (though none of it is explicit, luckily).