Special Effects Failure: The ending cutscene where Dino and Hoppy stomp on Dr. Butler has some very noticeable flickering on the animals. It's presumably done to not obscure Dr. Butler too much, but it looks more like the NES is low on video memory and is struggling to render the large sprites.
That One Boss: You're in for a world of hurt when you go into the boss battle against the Bigfoot-like character. Unlike most of the other bosses in the game, everything about the boss battle is completely randomized, meaning that there's no telling when a coconut is going to fall from the trees above or the Bigfoot guy will toss a difficult-to-avoid bug at you, resulting in a boss fight that can be nigh-impossible if luck isn't on your side going in. It's not so bad if you go into it with a bunch of coins with which to use special attacks, but if you neglect to make sure you do...
That One Level: The final level is swarming with enemies and tricky jumps, and the Final Boss is no slouch either.
Watch It for the Meme: The game received more attention thanks to the popularity of 7 Grand Dad.
It predates the discovery of the bootleg rather than the bootleg itself, but this hack ofSuper Mario Bros. 3 (somewhat inexplicably) features Flintstones characters existing in a Mario game before it was discovered that 7 Grand Dad did the same thing in reverse. To top it off, Barney's sprite used in Blue Mario Bros. 3 is the same one used in this game. (And the bootleg.)
The appearance of Mario in Fred's clothes can now be (sort of) realized in an official Mario game; Super Mario Odyssey enables Mario to wear a caveman tunic, and if you leave Mario's trademark hat on him while he is wearing it, it does bear a resemblance to the infamous sprite. (The outfit itself is actually based on an outfit worn by Mario in one of the German Club Nintendo comics when a time-travelling Mario visits the Stone Age.)
Memetic Mutation: The title screen of 7 Grand Dad, the bootleg Mario character it features (both Grand Dad on the title screen and the Mario/Fred mashup player character), Joel's reaction to it when he found it in a bundle of bootleg Mario games, and the 8-bit version of the Flintstones theme featured in the game have become infamous.
Super Mario Bros. 3 (somewhat inexplicably) features Flintstones characters existing in a Mario game before it was discovered that 7 Grand Dad did the same thing in reverse. To top it off, Barney's sprite used in Blue Mario Bros. 3 is the same one used in this game. (And the bootleg.)