Totally Tetrisized

Kevin and Simon Belmont are chillin' out, maxin', relaxin' all cool, shooting some b-ball outside of school playin' some kind of quiz game, at which Simon is apparently dominating, Princess Lana strolling in and claiming they've been playing it for hours, but Kevin's only excuse for such laziness is "it's so cool." Simon then answers "flood" to "what is a river that's too big for it's britches" and thanks to the television being kind of wacky, gets a flood in the face.
 

The television starts acting up and the game is replaced by a staticy plea for help from Mayor Squaresly, and Lana somehow gets the message that her brother Lyle is in trouble, despite the fact the mayor only utters four barely-comprehensible syllables in the message. Simon counts himself out, claiming he's had "enough hair-flattening experiences for one day," but everybody ignores his vanity and drags him along anyway.
 

They arrive in Tetris Land and find it to be completely empty, wondering where everyone has gone and where that big giant castle was the last time they were there. Naturally, Kevin has to comment on how it feels like they're being watched.

"Hmm! Who are these jokers? I thought get rid of all those Tetris troublemakers!"

They suddenly hear a scream for help coming from one of the alleyways, which Simon Belmont steps up to the task of investigating. The mysterious watcher then reveals himself to the viewers (only two minutes in!) and laughs over Captain N and the N Team, mocking their ineffectiveness in stopping his as-of-now unknown scheme, and creates a wall in front of Simon for him to crash into.
 

Kevin and Lana pick up Simon, explain their bad feelings about this place, what with the street somehow becoming a cul-de-sac, but press on in their search for Mayor Squaresly through other means. Suddenly, the buildings start collapsing! Kevin naturally reaches for his Zapper, though Lana stops him and says that the blocks look alive.

They make a mad dash for the Chamber of Tetris, the safest place there is, apparently, all the while blocks keep falling down. Kevin makes use of his gamepad belt to leap over a wall he could've just walked around, only to land on a bucking bronco block! Lana, naturally, just leaps into the sky and conveniently happens to land on a car block. 

Simon, meanwhile, suffers the fate of all comic relief characters and nearly gets his ass squashed flat and arrives at a dead end, uses his whip to knock out a tile, leaps through into nothingness and then opportunely lands on Lana's block.

Meanwhile, Kevin's block is still bucking and rearing, only for it to finally throw him off and onto Lana's block as well. Lana's streak of good fortune nearly ends when it crashes into another block and sends them all plummeting to their doom...

That is, it lasts out for another while thanks to Simon Belmont having a parachute in his backpack.

They arrive inside the Chamber and believe everything's going to be hunky dory, only for giant robot Tetris block monster to stand in their way. And ordinary not-friendly Tetris blocks to surround them in a hostile manner. Yipes! However will they get themselves out of this one!?
 

By revealing it was just Mayor Squaresly in a big suit, naturally. Relieved the heroes have arrived, he explains (using fade-out and having Kevin repeat the bare basics of it, naturally) that the Puzzle Wizard has taken over all of Tetris Land and has Tetrisized anyone who fought back. Lana goes in a crying fit over hearing that her brother Lyle went to challenge the wizard and never came back, but they shut her up by deciding to go to the castle themselves, Squaresly tagging along due to not wanting to be around when his badly-made robot falls to pieces.
 

Giving in to more cartoon clichés, they arrive at the Puzzle Wizard's castle and claim that getting in looks too easy, only for Tetris blocks to emerge from the bridge as they cross over and start harassing them. Lana saves the day by kicking one, knocking them all down in a domino effect and sending the last one into the moat for good measure.

Entering, the Puzzle Wizard greets them, claiming he's been expecting them and states "you won't be needing these" as random arms take away Kevin's Zapper and Belmont's whip, an action they don't react to at all, just standing perfectly still the whole time. It's Super Mario World's Fire Sale all over again!

Lana marches up to the Puzzle Bastard and demands to know what happened to Lyle, though he merely says to find out herself, suggesting she pick out one of the blocks from the walls, but nobody bothers.

Squaresly doesn't like this situation at all, though the Puzzle Wizard gives them one chance to save themselves by playing a game, so Simon steps up to the task. Lana, being a woman in a 1980s cartoon aimed at a young audience, is given the role of stating the very obvious to the dumber characters that this doesn't look good, and the Puzzle Wizard proves it by getting his game show narrator to show that if they lose, they'll get turned into blockheads!

Simon doesn't like this very much, but a guard prevents his exit so he has no choice in the matter but to go along with it. Riddle time!

"I have... fruit salad! No, apple sauce! No, apple pie!"

Kevin steps in to call Simon a dumb-dumb and to just put two and two together, and Simon gives "two" as his answer. Puzzle Wizard responds by using a ceiling-mounted gun to turn him into a blockhead.

Squaresly really doesn't like this and makes a break for the door, only to get zapped as well. Kevin demands the Puzzle Wizard stop being a dickhead and play some real games, prompting Lana to go "I can't lose you too!" The villain agrees, trapping Kevin in a glass panel and treats him to a deadly game of...

Real Tetris.

He has one minute to score 25 points or else he's a goner, so Lana uses that time to begin looking for Lyle among the blocks. The number of falling blocks slowly increases and Lana fears she'll never find her brother, only to find his ring protruding from a block!

Using her tiara to wedge it out, the ring flashes and Lyle is back to his usual, ugly self! Meanwhile, Kevin gets the 25 points with ease, making use of his gamepad belt, only for the Puzzle Wizard to decide to Tetrisize him anyway, simply because he's an absolute asshole.

Lyle steps in and makes use of his ring to deflect the ray onto the Puzzle Wizard, who instead of being Tetrisized, merely discombobulates and screams for a bit before finally vaporising.

With the day saved, apparently, and Mayor Squaresly thanking Lyle for his great work, Lyle thanks his sister and Kevin for saving the world and all that. He then asks where Simon is, his absence explained that his squareness is taking a while to wear off, so until then he's being used as a doorstop. Everyone laughs at the man with the disability.

Mayor Squaresly sounds exactly the same as the wizard from Return to Castlevania. I mean exactly the same. Budgeting!

So, uh, what exactly is the threat in this episode? The citizens of Tetris Land already appear to be blocks, more or less, so what is turning them into blocks again going to do?

So many uses of "blockhead" and I didn't once make a Peanuts reference. Good grief!