DM of the Rings deconstructs Tabletop Games, especially of the fantasy variety. The Lord of the Rings was basically the Trope Codifier for Fantasy Literature, with an epic plot and massive, meticulously crafted backstory. For decades now Roleplaying Games have often been based on fantasy stories and set in fantasy worlds... but you know, the actual progression of a roleplaying game doesn't look a thing like a fantasy novel, certainly not a good one. DM of the Rings takes several familiar player archetypes and transplants them into LOTR, and it's a disaster. The GM needs to use Railroading on the players every step of the way. Left to their own devices, they would have killed the elves of Lorien for the loot. They also complain endlessly about the boredom of the story (there's nothing to fight but orcs over and over again and Eldritch Abominations like the balrog, which their characters don't have the slightest chance against) and the way all the battles and side missions are entirely irrelevant to the main plot.
The side story Magical Girl Mina can be considered a deconstruction (or possibly reconstruction) of the magical girl genre. Mina is far from stereotypical proto-MG and does not adhere to any of the expected cliches, tropes and quirks (despite Tsunami being explicitly instructed to scout those traits) but is smart and fit and very inquisitive about how magic works and can be used. On the other hand Mina never reacts to the weirdness "normally" (such as fleeing or avoiding the situation) but accepts it with cautious curiosity.
Erfworld is a world where Tabletop Strategy rules are literally true, such as citizens popping in fully grown and a defeated team being frozen in time until someone comes to try and kill them. The more the rules become clear, the creepier everything starts to become.
It also deconstructs the typical Strategist with Parson's reaction to the aftermath of the Battle For Gobwin Knob. Instead of being proud and/or relieved that he won the battle against impossible odds, he is horrified by the death and destruction he has caused, so much that he steps down as Chief Warlord in favor of Ansom.
The Pixel Art ComicKid Radd, while largely light in tone, presents a "video game characters living in videoland" scenario where it's a very real problem that many inhabitants are innately armed and know nothing but killing. They know why they were created, and they don't like it. The player character Radd goes from slacker to Determinator because he always had the latter's mindset, but started his days in a game under the player's control, so he had to learn initiative completely from the ground up. Upon being freed, Radd needed instructions to walk independently.
It's Walky! could arguably be seen as a deconstruction of the goofy 1980s cartoons creator David Willis is a fan of (mostly G.I. Joe and Transformers). Sure it features a unique special forces group, SEMME (who were initially based on GI Joe) with an eccentric line up of operatives, who routinely foil the insane schemes of a Harmless Villain, but the eccentric operatives are soon revealed to be a bunch of dysfunctional screw-ups, and the Villain is in fact a Not-So-Harmless Villain.
Goblins: Life Through Their Eyes takes a good hard look at the Unfortunate Implications of labeling whole races Always Chaotic Evil. It portrays the titular goblins not as monsters but as people who live and love. It shows us that what Player Characters see as just an XP haul isn't so fun when you're the one they're killing to level up.
The entire premise behind Darths & Droids is that the Star Wars universe is the result of a group of Tabletop Gamers (including a 7 year old girl) making it up as they go along. It lends a whole new perspective to the storyline of the prequel trilogy. The entire mess on Naboo was the result of the Player Characters epically ruining a delicate, carefully constructed plan by going Off the Rails, and engaging in all the sins of The Real Man, The Munchkin, and The Loonie. Palpatine is actually a good guy overthrowing a corrupt regime, and trying to bring a semblance of stability to the republic. Darth Maul was just a Chaotic NeutralHired Gun who was only trying to work with the player characters, before they attacked him. To top it all off, some the most bizarre and unrealistic plot points, such as Naboo being governed by a 14 year old Queen exist because Jar Jar Binks is being played by a little girl.
In the Chapter 26 of the Spanish webcomic 5 Elementos, the author show the effects of a civil war in a world inhabited by lots and lots of people with superpowers.
Misfile can be considered a broad deconstruction of the Gender BenderTransformation Comic, showing how much it would actually suck if you were transformed into the opposite gender and didn't have those kind of tendencies to start with (the part frequently ignored by TG comic fans who wish something like that could happen to them.) Ash is depicted like a real transgendered teen would be (literally a boy trapped in a girl's body), with a realistic level of distress to not only the biological and social changes, but to also having the entire foundation of your world and personal identity ripped out from underneath you.
One could say Sluggy Freelance is something of a deconstruction of what it's like to live in a Fantasy Kitchen Sink. Eventually, the amount of supernatural villains you piss off (and the infamy among the inhabitants of said Fantasy Kitchen Sink that you gain through your deeds) will reach such a critical mass that your entire life will be swallowed up in a never-ending, breakneck onslaught of attacks and reactions to your attempts to defend yourself from said attacks from grudge-holding demons, psychopaths, monsters, conspiracies, Eldritch Abominations, Artifacts of Doom, evil Mega Corps, etc, etc. Being a fairly early webcomic, this has been subjected to a measure of Seinfeld Is Unfunny.