These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Super Mario Bros. 1
Alternative Character Interpretation: The manual states that the Goombas are what happens to traitorous Toads. If Princess Peach has great magic powers like the above entry suggests, who do you think is carrying out their sentences?
Anti-Climax Boss: The final Bowser is basically unchanged from every other one. Like the fake Bowsers in worlds 6 and 7, he tosses hammers, but that's it.
Getting to Bowser with an extra hit turns him into a complete joke no matter when you fight him. Just take a hit and then run to the other side and grab the axe before your Mercy Invincibility wears off.
Awesome Music: The Overworld theme is probably the most well-known song in all of gaming. The Underwater theme isn't too bad either.
Demonic Spiders: Hammer Bros. and Lakitus. The former throws hammers at an absurd rate that makes it hard to dodge and attack them, especially since touching the hammers at all counts as a hit, and jump a lot making it hard to hit them. Their jumping can often make jumping on them a risk, because unless you hit the top of them, then you get hit instead. They can also jump downward from platforms, meaning if they're on a set of blocks, trying to hit them from below can easily result in them killing you. Lakitus... oh boy... those bastards are on clouds at the top of the screen, and it's extremely rare to come across a point that lets you get high enough to hit them. For attacks, they drop spinies, which you can't jump on. So to recap, you, for the most part, can't hit them, and they drop a constant supply of enemies you can't kill unless you have a fire flower.
Everyone Is Satan in Hell: Basically, as some players noted, Mario's design resembles Soviet leader Josef Stalin, Mario is the hero of the game, and the ending of a level basically depicts Mario putting down a flag that slightly resembles the peace sign and hoisting a flag that has the Soviet Red Star. In one Nintendo Power issue, this subject was discussed in the mailbag section, although the staff denied the resemblance, noting that Mario collects coins and is saving a monarch, even trying to put Mario's moustache on the Russian boxer/soldier from Rocky IV. It's much clearer in later games with more advanced graphics: the symbol of the flag that Mario pulls down is supposed to be a Bowser skull. In its 8-bit form, it resembles a human skull or a Koopa shell.
First Installment Wins: Sort of. While future games in the Mario series are just as, if not even moreso beloved in the fandom, this first one is undoubtedly the most famous.
Porting Disaster: To an extent, Super Mario Bros. Deluxe on the Game Boy Color. Mario's handling is VERY slippery-slidey, even moreso than his brother in the sequel. The reduced screen size also becomes a massive hindrance.
You Should Know This Already: The princess is in world 8. When this game was new, players might have wondered how many times Mario must go to another castle. Since then, several more Mario games have kept the princess in world 8 or chapter 8. So now players expect to find her in world 8.