In Moleville, there's a Whack-a-Mole like game where you whack Goombas instead. The mole is the one running the game.
Early on in the game, Mallow mentions that he can't jump. Apparently it runs in the family, as Nimbus Castle is designed so that no jumping is required to get around it.
Mallow grew up in a marsh. He is truly a Marshmallow.
Smithy is ruler of another world, uses a hammer as his weapon, can shapeshift, and with the four members of the gang besides Exor (counting the Axem Rangers as one entity), he leads a Five-Man Band that seek the Star Pieces… could Smithy have been intentionally designed as an Evil Counterpart to Mario?
Smithy is a blacksmith, Mario is a plumber. Both are blue collar occupations. And both didn't even realize there was anything to the Star Pieces when they first encounter eachother, simply continuing to do what comes natural to them, but upon learning of them immediately set their sights on having all of them. Hmm… The similarities go further: Both of them sport awesome facial hair of some kind (Mario a mustache and Smithy a beard).
Without the Star Road, no one's dream can come true. That also includes Smithy's wish of ruling the Mushroom Kingdom.
However, Mario and his party's actions end up fulfilling several of the unrealized dreams on Star Hill, most notably reuniting Mallow with his family. This could possibly point to An Aesop of working hard and perseverance matters more in realizing one's dreams as opposed to a magical wish-granting star.
The scenes with Gaz has him set Geno as a Parody Sue with how Geno usurps Mario's role and how Gaz treats his custom doll with more respect than Mario. Geno (or rather, the spirit inhabiting him) is wildly popular, reasonably developed, and useful on the front lines, which is a welcome bonus.
Why is Punchinello not part of the Smithy Gang despite being based on a weapon? The Smithy Gang are all based on archaic weapons that can be reused (knife, bow, spear, axe, sword, hammer), with most of these crafted by blacksmiths. Punchinello is based off bombs, which aren't produced by a blacksmith, are a much more recent invention, and can only be used once compared to the weapons listed.
Smithy's Lieutenants were sent to wreak havoc on Mario's world, but it does seem that they might have had specific goals:
Mack/Claymorton: Scouting. His Shysters/Shymores harassed the Mushroom Kingdom's Toads to learn about their daily lives and report back to Smithy. The Shy Guy resemblance helps them avoid being detected as an Outside-Genre Foe and get seen as Bowser's troops instead. Finding out that Mario was a credible threat to the Smithy Gang was a bonus. The intel on Toad behavior would later be put to use by Yaridovich/Speardovich when he impersonated Seaside Town's citizens.
Bowyer: Intel. After learning about Mack/Claymorton's defeat at Mario's hands, harassing the villagers of Rose Town would be a way to attract the plumber's attention. Locking Mario, Mallow, and Geno's attack or special commands helped Bowyer find out what they're capable of. A scout Aero could then report back about their abilities for Smithy to design a countermeasure like the Axem Rangers. Learning about the true value of the Star Pieces and Star Road was a huge bonus.
Yaridovich/Speardovich: Infiltration/Retrieval. Having learned some intel about how Toads act by Mack's Shymores, Yaridovich/Speardovich took Seaside Town hostage and split himself into fake Toads that (attempt to) behave like the Town's citizens. After learning about the Stars' purpose and Johnny's possession of one, he would try to convince Mario to get it for him.
Axem Rangers: Direct confrontation/Retrieval. Unlike the above three, they don't even need to harass a town as they're made for a direct confrontation — hence being The Psycho Rangers equivalent to Mario's team. Having learned about the threat that Mario and co. pose, the Axem Rangers lie in wait until the Czar Dragon was defeated, then attempt to retrieve the star, while confronting Mario's team if they pursued.
The mass-produced Machine Made copies of Smithy's lieutenants are of lower quality than the originals and are much easier to defeat as a result (though some of them have some slightly improved stats), implying that Smithy is sacrificing quality for quantity so he can quickly build a new army for a second invasion of Mario's world.note Specifically, Smithy is not taking into account how powerful Mario and his party have become since the beginning of the game, and as a consequence, has not scaled the Machine Mades' stats accordingly, making them very easy to take down. In real life, the question of "Quantity vs. Quality" informs most manufacturing industries, and it's a common belief that mass production results in lower quality products.
Giving a specific real life comparison, it's like how many people don't like redecos of Transformers toys because they use the same mold, and one of the problems that can happen is that the mold used gets damaged, so future versions of those products get defects. The molds may be getting damaged from making so many copies, or he's just using a material of different quality for each of them.
It may seem weird that Mallow gets the Star Rain spell instead of Geno, when Mallow's other spells are weather-based and stars are Geno's specialty. However, going by Final Fantasy conventions, Mallow is a Black Mage, and Meteor is usually one of the ultimate black magic spells. Another name for a meteor is a "shooting star," so Star Rain is just what Meteor would look like in the Mario 'verse!
Fitting that Mallow is a Black Mage, he wears the pants exactly like the iconic Black Mage character class from Final Fantasy I, III and V.
All of the characters have Playing Card Motifs when they use their special attacks: Mario has spades, Mallow has clubs, Bowser has diamonds, Peach has hearts, but Geno has… stars. But Geno isn't from the Mushroom Kingdom, he's an otherworldly being, so of course he doesn't fit with the card motif!
Alternatively, he does: Stars are often associated with the joker.
After the first boss fight against Bowser, a cutscene with Exor descending from the clouds and destroying the Star Road as he falls straight into Bowser's Keep is shown. After the title of the game disappears, the Star Road's fragments AKA the Star Pieces are seen falling. It's an easy-to-miss detail, but if you line up Bowser's Keep to the rest of the World Map, you'll notice that the falling Pieces' directions indeed line up to the locations you find each of them throughout the game.
"Then we could get rid of all wishes, and create a world filled with...WEAPONS!!!" From a metaphorical perspective, Smithy's speech can be considered foreshadowing because...
The reveal trailer for the remake begins with an exact replica of the SNES game's opening, only for an out-of-place shining light to fly in and turn the scene into the remake. The same light later appears during a brief shot of "♡♪!?" becoming Geno, implying that not only are they one and the same, it was granting the audience's wishes for a remake or at least a port on the Nintendo Switch Online catalog.
In the remake, there's one Toad in Peach's throne room wearing a blue vest, the rest are wearing red. He has a different line too; implying he's the Toad from Super Mario Bros. 2 while the rest are generic NPCs. (They were all wearing blue vests in the original)
All the Toads in Rose Town have caps with concentric circles. That's why Bowyer was attacking them in the first place — they look like targets. Bowyer's Monster List profile in the remake even alludes to this.
The reason Chef Torte's cake comes to life and attacks everyone, is because, according to a wish on Star Hill, it's his wish to be the greatest chef. The Star Road being damaged made his wish not come true in the worst way possible.
In the remake, the gang, are awfully chummy with Booster when they visit him, despite the grief he caused them, especially for Peach. Given how often Peach has been kidnapped by Bowser, who is traveling with her no less, it makes sense how he was Easily Forgiven, especially since Booster's intentions were not of malice, just him truly not understanding what he did wrong.
With the remake's higher quality cutscenes, we can now deduce why the star spirit chose to inhabit the Geno doll, and why it said it looked the strongest. The other dolls seem to be made of plastic or other softer materials, while the Geno doll is made out of wood. Thus, it probably was the strongest doll. Additionally, considering Mario, Peach, and Bowser's popularity, their dolls were likely mass produced. However, Geno was one of a kind, presumably made specifically for Gaz by the local woodworker. The Geno doll was a wish granted with hard work and love, and that's probably why the star spirit chose it.
It's rather interesting and fitting that both the first proper boss (the Hammer Bros) and the final boss (Smithy) are hammer-themed and use hammers to fight.
Yaridovich/Speardovich's weakness is lightning. This is actually quite fitting — he's a very tall metal spear holding a long metal spear, which makes him an Improvised Lightning Rod!
The fight against Bowser at the very beginning requires Mario to attack the chain of the chandelier the Koopa King is on. So Mario must, instead of attacking directly, go behind Bowser in order to get what he's standing on to fall? That's how he's defeated in the first Super Mario Brothers!
Smithy is vaguely mechanical-looking. The design of the battleground of the second fight against him features a number of Smithy-esque heads littering the area. How many more Smithies are there? Who is making them?
Mallow can use the special attack "Psychopath" to read enemies' thoughts. Near the very end of the game, Mario and company battles against the Director of Smithy's Factory. Now, in the Japanese version, Mallow's Psychopath reveals that this factory staff had been involved in "a worker's labour union", had "his son's (presumably Japanese-style high-school/uni-entry) examination", and also made a "career change", possibly hinting that he had "a long working life", who just happened to be a father who needed to support his family.
The remake, with its better graphics, has a pair of glowing eyes peeking out from Johnny's mouth—is that somebody Johnny ate, or is Johnny wearing a full body shark costume?
He implies at one point that he can't live on land out of the water for too long, which heavily support the former.
The Monster List entry for his first fight says that he slew a man-eating shark in his youth, implying he might just be wearing its hide... Which might be worse, as that means he's a dude wearing a shark's skin in charge of a crew of actual, sapient sharks.
The remake paints Valentina's abuse of Dodo in a much darker, Realism-Induced Horror light. According to Dodo's Monster Compendium entries, the first mentions that he imprinted on her, sees her as his mother, and is doesn't know that he's not actually the prince of Nimbus Land. The second entry mentions that he resents Valentina for abusing him, knows that she isn't his real parent, but still has Undying Loyalty for her because he's indebted to her for raising him. Dodo is essentially an adopted child who's abused and gaslit by Valentina while resentfully conditioned into following her, and this emotional abuse is likely the cause for his laziness, gluttony, and especially his foul temper. Such a thing can all too happen in real life.
