Adapted Out: Most of the C-list mecha (Datas, the Mystic Brothers, the Exotic Brothers, possibly Gosei Wonder) are gone, as with the accelerated timeframe the Rangers are literally debuting new powerups every episode as it is. Notably, the show is still using a combination that originally involved Datas: the Ultra Gosei Great Megazord (Toywise, the combination is done with three new vehicles that work with the Brothers Zords and a motorcycle with the Ultra Change Zord). Gosei Wonder, at least, looks like it'll be getting a toy release (as "Gosei Jet"). There's also little to no sign of Robogog being carried over.
Aliens Are Bastards: Implied by Vrak in his first confrontation with the Rangers in "United We Stand":
Noah: What do you want?
Vrak: What do any alien beings want from other civilizations?
Arbitrary Skepticism: The teens are shocked to learn about the existence of aliens and Power Rangers. Thing is, Earth has already suffered a full-scale alien invasion once before, and the Power Rangers have been known public figures both before and after that. What makes it especially glaring in this case is that Gosei mentions that Zordon was his mentor, which very firmly establishes that the previously mentioned alien invasion did happen. (Their teacher, Mr. Burley, also believes in cryptids, but that's at least a form of weirdness that hasn't had public exposure in the Rangerverse.)
The Artifact: The show has been trying their hardest to avoid all the text on the Ranger's cards from becoming this, keeping most of the names for them (although there are still some problems, like the Sky Brother's card still saying Skick Brothers.)
Bowdlerise: The red parts◊ of the monster Irian from Goseiger were painted a dark blue for her Megaforce counterpart Beezara, making them look less like Non-Mammal Mammaries and more like part of her body armor, since that's something that just won't fly on an American kid's show. It's also fairly safe to predict that Metal Alice's Torpedo Tits won't make the jump either.
The Cameo: Saban is lining up former Rangers to make appearances in Super Megaforce.
Dub Name Change: Averted by the mecha, which go by their Goseiger names with "Megazord" on the end (for example, Gosei Great becomes the Gosei Great Megazord). Other terms carried over include "Warstar", " Dynamic", "Victory Charge", "Twistornado", and "Metal Alice". A lot of this probably has to do with sticking as closely as possible to Gosei Card Stock Footage.
Dull Surprise: Troy. Most evident in "Robo Knight" where his expression doesn't change at all when Robo Knight doesn't shake his hand - this has caused Rangerboard to joke that Troy's more robotic than the actual robot is. However, it is mostly averted with the other Rangers.
Early-Bird Cameo: Sixth Ranger Robo Knight appears in the first episode when Troy dreams about the Legend War, which of course hasn't happened yet. Additionally, the Gormin from Gokaiger appear, though we haven't learned their American names yet, with Troy Dreaming of Things to Come.
Egocentric Team Naming: Not the team name, but much of the Rangers' equipment is named after Gosei. The morphers also seem to be his face in miniature - which is at least better than Goseiger, where Master Headder's face was the team logo and was thus plastered oneverything. Then again, Troy sees said logo on Robo Knight and says it looks like Gosei...
Establishing Character Moment: Troy's optimism is on full display when asked which species is most likely to survive, saying "Humans. Because together, we can accomplish anything."
Emma's love of the environment, Noah's nerdiness and Jake's crush on Gia are also established in short order.
Expy: Gosei and Tensou are the next Zordon and Alpha. Gosei mentions that Zordon was his mentor. Though Tensou's more like Johnny 5 than Alpha 5.
Robo Knight seems to be one of RoboCop with a similar voice and sound effects.
Evil Cannot Comprehend Good: In "Prince Takes Knight", Vrak assumes the Rangers abandoned Robo Knight after they called him out for endangering civilians; and is surprised when they come to his rescue anyway.
Foreshadowing: Insects and Robots are mentioned during science class as potential "stronger species". Insect aliens begin invading later that episode, and robot enemies will be antagonists later in the season. The third group of enemies was foreshadowed in the next episode, when we found that Mr. Burley has an interest in cryptozoology.
In "United We Stand", the Rangers first meet Vrak and Noah notes that he isn't an insect like the rest of the Warstar; and he's later seen with a newspaper with a headline about ocean pollution (hinting at the robots, who had a sea base in Goseiger).
Fake Ultimate Hero: A customer of Ernie's Brainfreeze, named Jordan, claims to his peers that he's the Red Ranger, but is rather cowardly.
A Form You Are Comfortable With: Jake comments that Gosei looks like a Tiki head. Gosei replies that he has taken on a form that "you would be comfortable with".
Gaia's Vengeance: Both the mutants and Robo Knight are this, though in different flavors. Robo Knight's mission is to defend nature that's threatened, while the mutants want to take the threats and escalate them to a full-on eco-disaster for revenge. It's also probably a good thing that Robo Knight sees the mutants as the threat, not humanity.
Humans Are Bastards: The mutants believe this. They made their home underneath an old toxic waste factory, where they were formed from the waste that seeped into the cavern underground. They view their plan to turn Earth into a toxic wasteland as simply finishing what humanity started.
Gosei and Tensou being blatant Expies of Zordon and Alpha. Justified; Zordon was Gosei's mentor. Plus, the local hangout owner is named "Ernie" like his Mighty Morphin' counterpart.
In the cast wardrobe◊: Blue Ranger Noah in smart specs similar to Billy's, while Pink Ranger Emma sports shorts like Kimberly.
The premiere has numerous Call Backs to "Day of the Dumpster". Both have the teens' arrival at the Command Center include a brainy Blue Ranger-to-be fascinated by the resident robot, and there are a lot of dialogue nods including an exchange between a giant head and a robot about needing teenagers, the Red Ranger delivering the line "[Zordon/Gosei] said these morphers would give us power.", and the Pink Ranger joking about helmet hair.
Lampshade Hanging: In the episode "Robo Knight", Gia lampshades the Make My Monster Grow trope when she shouts, "Guess we should have expected this!"—as the monster is growing in front of them.
Limited Wardrobe: All five Rangers have worn the exact same outfits in every episode, barring only an occasional wardrobe change. Sure, the franchise uses this trope often, but it's more noticeable this season because it's civvie wear and not a uniform or something.
Lull Destruction: Averted. The series is written with a fairly serious tone, and the fights are, in general, rather silent outside of the grunts of the Rangers fighting.
Magitek: Vrak's Zombats can bring fallen monsters back to life, making their function a form of necromancy; however, Vrak describes them as being robotic. Vrak's character bio also mentions that he is capable of performing alien magic, which seems to be this trope.
Meaningful Echo: Troy stops a bully in "Who's Crying Now?" by stating that a) you shouldn't be bullying people around and b) every small creature doesn't need to be picked on. The words get repeated later in the episode when a) the kid Troy saved from the beating uses the first set of lines to save said bullies from Creepox, and b) the bullies repeat the second set to prevent the group from squishing their target's insect friend, now having a true change of heart.
Thus, there are several references to all seasons, such as It's Morphin' Time! and Samurai's "Go Go Samurai" as "Go Go Megaforce"
Speaking of Samurai, the season's theme is similar to the Samurai theme. But proven different with a scene from "Who's Crying Now" When Troy activates the Ultra Gosei Great Megazord's Victory Charge, part of the theme is playing in the background and is similar to In Space's theme.
Mythology Gag: Besides the many references to Mighty Morphin', the names "Gosei" and "Tensou" are taken from the original Sentai but used in a different context.
When the first Monster of the Week is summoned, his boasting ironically includes the words "Power like they've never seen before". This is extremely close to the first lyrics from the original "Go Go Power Rangers" theme song.
"It's Morphin' Time!" has returned as an additional Invocation before the official morphing call.
The local hang out owner is named Ernie, after a character with the same role from the first four seasons.
No Pronunciation Guide: In Japanese, "Tensou" is pronounced "ten-soh". Tensou in Megaforce is pronounced "ten-soo".
This also applies to Vrak. Even Admiral Malkor doesn't know how to pronounce it. He's called him both 'v-ROCK' before and 'v-RACK'.
Non-Indicative Name: Harwood County is actually a city. Well, it could be both - there are a number of cities big enough that they're considered counties as well - but it's odd that "County" is in the proper name.
Our world was once a safe and happy place, until evil aliens arrived with one plan: to destroy Earth! Gosei, Earth's ancient guardian, awoke, and called on a new team of teenagers to fight off this new threat. They are the Power Rangers Megaforce!
The Something Force: The first Power Rangers series to invoke this trope while combining the word "Force" with the season subtitle's first term, resulting in the one-word subtitle of Megaforce. Additionally, unlike other The Something Force seasons, this season's theme isn't necessarily indicated by the word preceding "force" in the title; the subtitle merely utilizes a generic prefix.
Spell My Name with an S: The season is titled Power Rangers Megaforce, although variable spellings of "MegaForce" and "Mega Force" can occasionally be seen. These variants are likely arising because past seasons containing the term "Force" in the subtitle have always treated Force as a separate word, whereas Megaforce is the first instance of the term "Force" being combined with another term to make a compound-word subtitle.
Coincidentally, the usage of a compound word helps in averting Acronym Confusion (as of 2013), as Megaforce can use the initialism PRM rather than PRMF (which is usually used to refer to Power Rangers Mystic Force).
Spoiler Opening: The title sequence includes clips of the Gosei Ground Megazord and Vrak's ultimate form, long before either is in the show.
Toilet Humor: Calling Samurai's Mooks "Moogers"note it resembles the word "Boogers" may have been merely unfortunate; but this year, calling the snot-green guys "Loogies" had to be on purpose. It doesn't help that they appear from green slime, and that in episode 3, the Monster of the Week can turn people into Loogies by sneezing on them).
Trailers Always Spoil: Even just the first press release reveals that the villains aren't just the Warstar; there are going to be three villain groups, and they're going to be directed by a fourth party. Just like Goseiger, which had three groups, but Vrak's counterpart Buredoran was involved in all three and was eventually revealed to be the Big Bad manipulating them all.
Also, the Sixth Ranger, Robo Knight, is part of the earliest promotional material and toy releases.
The Virus: The third Monster of the Week, Virox, can turn ordinary humans into Loogies by sneezing on them. Then those specific Loogies can sneeze on more people and turn them into Loogies, and so on. Luckily the virus can be cured by killing Virox.
What the Hell, Hero?: In the ninth episode, Robo Knight is under fire from Mooks and jumps to the side, while civilians are behind him. While the Rangers save them, they do call out Robo Knight on him putting the civilians at risk.
Not helped by Robo Knight not even trying to pull a Jerkass Has a Point, which he probably would've been able to do by explaining that him not taking heavy damage is more important to him then a few civilians.