Anticlimax Boss: The Emperor of Blobolonia. All the player has to do is throw an apple jellybean at the Blob in order to knock down a jar of vitamins, which instantly kill the Emperor. He doesn't even attack the duo.
Broken Aesop: The original game seems to be saying sweets are bad (marshmallows and chocolate kisses can kill you, and vitamins are used to destroy them) yet jellybeans are the Blob's source of power and peppermints are traded in for extra lives. Cherries (or more accurately, cherry bombs) are among the things that kill you.
Good Bad Bugs: The infamous coconut trick which allows you to remove lots of enemies. There is even a glitch where you can get a glimpse of a final boss and remove all the enemies that way.
Nintendo Hard: Only a handful of lives, no continues, and a finite number of jellybeans that mean squandering them can render the game unwinnable.
Anticlimax Boss: The Emperor can be this. It isn't as bad as in the NES original, but all the player has to do is drop a rock on their head. Once. It's a lot harder than it sounds, but still fairly easy. Thankfully there's another boss after that, and justified that it's likely a recreation of the disappointing final boss of the NES game, but harder and longer.
Breather Level: Challenge Level 2-4 is pretty easy—it's a lot of running around inside the Cola Bubble, which is Nigh-Invulnerable. This is a good thing, because Challenge Level 2-5 was probably designed by someone on the dev team who was bald and didn't want to feel so alone.
Most challenge levels involving the Cola Bubble or the Root Beer Rocket tend to be this (except for the final rocket level, which is surprisingly long and brutal.) The penultimate challenge level is also pretty easy too, consisting of more rampaging with Blob's mech form.
Goddamned Bats: The airborne mine enemies tend to gather in huge clusters, just waiting to explode on you. And you really have to avoid that blast radius, too. They doubled as Demonic Spiders since you're a One-Hit-Point Wonder.
The birds that steal your jellybeans when you try to throw them. It's oh-so-satisfying whenever the game gives the player a chance to trick them into flying into a blob mine and blowing themselves up.
That One Boss: The Beast at the end of World 2. It's a pain in the patookie for two main reasons: 1) The Beast is fast, agile, and adroit. The Boy is not. 2) No matter what he gets attacked with, the Boy dies in one hit, and if he does, then you have to start the whole fight over again from scratch. And you can't quit mid-fight and pick up there, either—if you want to stop, you have to go through the whole level over again. In an article for Gamasutra, the developers themselves admitted that they didn't think this boss through enough. Oops.
Visual Effects of Awesome: The graphics in the 2009 game. Every movement of the Boy, the Blob, and the enemies is lovingly hand-drawn. The backgrounds exquisitely painted. The developers said they wanted a deliberately nostalgic, warm feel, and knew only traditional animation would get them that. And it looks awesome.
WayForward has had a history of this, with their previous game Shantae.
is lifted straight from the "Raiders March"