Don't Judge A Book By Its Cover

To furthermore help you understand what a genre deconstruction is, I'll be giving two examples which will include an anime with a specific genre and another anime which is the same genre,except the second genre will focus on that genre's deconstruction.

What Is A Deconstruction?

Deconstruction, a method of analysing something(typically a form of media such as a book or movie)through a viewpoint which is the complete opposite of what it is originally intended to be like.

Magical Girl Genre-Sailor Moon

Sailor moon is an anime revolving around a girl by the name of Usagi Tsukino, an average student whose life is turned around when she saves a cat and from doing so is granted the role of sailor moon(an individual who is to protect the earth from incoming dangers). If you didn't already know of the magical girl genre than I'm preety sure you have seen an example of it, one of the most popular examples of the magical girl genre would probably have to be sailor moon.
The magical girl genre(if you didn't already know) is the genre of anime involving female characters with magical abilities.The magical girl genre originated back in 1953, when a manga by the name of Princess Knight was released and so the magical girl genre came to be.

Magical Girl Genre Deconstruction-Puella Magi Madoka Magica

Puella magi madoka magica is an anime about two middle schoolers by the names of Madoka Kaname and Sayaka Miki whose lives are changed when they encounter a cat like creature by the name of Kyuubey who is able to grant wishes but with having that wish granted must become a magical girl. Now this anime at first glance is what looks to be a typical magical girl genre anime but as you continue to watch the anime than you'll realize that it is not the case, in fact it's the opposite of magical girl genre anime or you can say that it is a magical girl genre anime with changes made to it that allow it to be a somewhat different approach to something(in this case, a different approach to the magical girl genre).
Its start allows you to believe that you are watching a typical magical girl anime but later on the story keeps on becoming darker and darker and so you see that being a magical girl isn't what sailor moon shows it to be like. I myself did not enjoy the anime but I like to see the good in everything and this anime showed a great example of a magical girl genre deconstruction.

Mecha Genre-Gurren Lagaan

The anime that come to mind when hearing of the mecha genre usually include such anime such as the gundam franchise, code geass, neon genesis evangellion, and my favorite mecha of all time, gurren lagann. I'm not saying that it's bad because gurren lagann put all of those features that a mecha anime is composed of and furthermore made it to what others can call a masterpiece(I don't believe so but I do believe it to be one of my favorite anime).
Gurren lagann is about two individuals by the name of Simon and Kamina who live in an underground city who stumble upon a key that is used to operate a weapon(a weapon they name lagaan) which they use to fight off a surprise attack from above, with the help of another individual by the name of yoko and after defeating this creature, leads to them starting their journey of exploring the outside world. Gurren Lagann might be one of the greatest mecha anime of all time(in my opinion)but than again it contains many of the features that all other mecha anime contain.
The mecha genre is the genre of anime that typically revolves around individuals who take controll of machines or robots(typically the machines or robots size are bigger than that of a humans size).

Mecha Genre Deconstruction-Neon Genesis Evangellion

The fact that this anime takes a darker approach to the mecha genre is what I particularly enjoyed because other mecha usually focused on protagonist fighting wars usually being victorious but neon genesis evangellion took a much different approach to the mecha genre, a much darker approach to it that revolved around a not so brave protagonist who has tons of problems(yes many mecha anime revolves around problems but not much revolve around a teenager, a brave one at least because not much are as realistic as neon genesis evangellion was).
Neon genesis evangellion is an anime that takes place in the year of 2015 where humanity is very close to their destruction and their last hope lies in a group by the name of NERV(an agency under the United nations) and their evangellions,giant machines capable of defeating the angels(enemies posing a threat to the planet), but the only ones capable of piloting the evangellions are a group of teenagers which include the protagonist, shinji ikari, the son of the founder of nerve, whom haven't seen face to face in years.

Super Hero Genre-My Hero Academia

My hero academia revolves around a world in which quirks(or super powers) are inhabited by 80 percent of humanity and the rest of the 20 percent without having any quirks such as the protagonist Izuku midoriya who wishes to enter UA High, a school specifically to train others to become heroes. Lots of anime come to mind when hearing the super hero genre but the most famous are one punch man and of course my personal favorite, my hero academia.
The history of the super hero genre dates back to the year of 1952, the year in which the astro boy manga was released and the start of the super hero genre for anime. My hero academia takes all of which a super hero genre type media should have and combines them together to make something huge, the next big anime in my opinion.
The super hero genre is the genre of anime which typically involves characters who contain a super power of some sort that others do not posses.

Super Hero Genre Deconstruction-One Punch Man

One punch man is yet another personal favorite anime of mine and what I enjoy most about it is that it keeps most of the qualities that a super hero anime contains but than again gives it a comedic twist, one where the protagonist becomes a hero without caring for its responsiblity and by inhabiting enormous strength. One punch man is anime that revolves around a man by the name of saitama who's hobby is to become a hero and he does so by training non stop for 3 years straight, little does he know that this would lead to him becoming a little too strong, too strong that he is able to take his enemies out with one punch.
The comedic element of having an overpowered character at the start of an anime is what I enjoyed greatly of the anime, it is true that anime audiences have seen this before but it's unusual to see this in a super hero anime.

Isekai Genre-Drifters

What I enjoy most about the Drifters anime is it's uniqueness of having past historical figures being teleported into a fantasy world where they are to battle, the fact that it was made by the same creators of hellsing/hellsing ultimate(one of my personal favorite anime of all time), and because it took the isekai genre to a more mature direction, one where the adults could be furthermore intrigued in the isekai genre.