Artificial Stupidity: Since it's largely Brawl AI, the CPUs are incapable of fully utilizing the advanced techniques technical potential of the game (e.g. chaingrabbing and DACUS*
a Dash Attack Cancelled Up Smash. It involves performing a dash attack, and then very quickly pressing Up and the throw button simultaneously
). As of Demo v2.1, there have been slight tweaks to the character's AI, including all CPU-controlled characters being able to wavedash, recover more efficiently, and four characters are capable of L-cancelling*
the Space Animals (Fox, Falco, and Wolf), and Captain Falcon
Attack Reflector: Everyone can achieve this if they perfect shield, though it's much harder than using a relevant special move to do so.
Combos: Although comboing is a mainstay of the Fighting Game genre, this is the first time in Smash that combos of such complexity are intentional and integral to the gameplay.
Doing It for the Art: So far, the team has independantly spent two and a half years working on this project, all for the love of Smash. That's longer than the development times of Smash 64 and Melee!
Easter Egg: As a nod to the noob quality/ general incompetence of the Wii remote, selecting a character with said controller makes the narrator's "Failure" sound effect play through the Wii remote speaker.
Fan Remake: Of Melee's and Smash 64's characters, stages, animations, and physics.
Fan Sequel: To Melee, since Smash as a series has general installments rather than direct sequels (in terms of gameplay)*
This is due to Sakurai's insistence on making every additional game drastically different from the last, since he isn't much of a "sequel" person in general.
; since Brawl heavily deviated from the gameplay of both Smash 64 and Melee, Project M is made to be the true sequel to Melee.
House Rules: Somewhat averted in that, as opposed to Brawl's settings, the conventional competitive set is now default, which saves players the trouble of ever needing to set the rules manually. 4 stock, 8 minutes, and team attack on. Also, the "buffer" setting, introduced in Brawl+, is present, though it isn't considered tourney-legal.
Melee and Brawl have forms of taunt canceling, but to very minimal extents. See ssbwiki.com for details.
Meteor Move: Footstool jump is one of the few techniques retained from Brawl. Essentially, it gives every character a meteor smash, albeit a bad one. Unlike in Brawl, where it's executed by pressing a jump button while on an opponent, it's done with a separate input from the regular jump, so it can be mapped to a different button on the controller (up on the d-pad by default), and it can't be done accidentally.
No Sell: Characters that tether recoverer in Brawl suffered from extremely easy ledge-hogging; when a character was occupying the ledge, the tether couldn't detect the ledge, so the user wouldn't be able to recover. In PM, tethers are no longer dependent on ledge occupation, so the tethers can work without being blocked off. Therefore, multiple characters could grapple to the same ledge at once, with an additional character occupying the ledge. When a tethering character pulls up while the ledge is occupied, he/she ledge-jumps instead.
Shown Their Work: It's clear that most members of the Project M team know a lot about the games of the characters in Smash. Many characters were given both functional and aesthetic changes that reflect their incarnations in their previous games.
Obvious Beta: Not really a beta, but the first demo fits this trope. Compared to the more recent developers' builds and the second demo, the first demo is very outdated, and it inversely shows how much "Melee-ifying" the team has accomplished in months.
One Letter Title: Though some playtesters prefer to call it "Project Melee".