YMMV / Smash Up

• Complacent Gaming Syndrome: Due to their ability to rapidly magnify the number of minions and actions that can be played in a single turn, which plays into literally every other factions primary strategy, you're almost guaranteed that someone will select the Wizards faction in every single game you'll ever play.
• Game-Breaker:
  • The Zombie faction is able to discard their own cards, then easily play cards from your discard pile, allowing for Zerg Rushes. This ability is extremely useful, and most factions rarely have such abilities. The Robot faction has weak minions that play more minions and then power up the minions in play, forming a formidable, high-power army. Combine both Zombies and Robots? Say hello to an even bigger Zerg Rush of tough minions that just won't stay down!
  • The Invader minion in the Alien faction instantly gives one victory point when played, and the Alien faction has many cards that allow the player to withdraw the Invader back to their hand, often on the same turn. Destroying the Invader is tough, and effectively impossible if paired with the Zombies, and even if it is destroyed there's still another one waiting in the deck. It's very easy for an Alien player to just waltz to victory one point at a time while the other players rush to fill up bases.
• High-Tier Scrappy:
  • Zombies, due to their ease of drawing and playing cards from the discard pile, allowing a Zerg Rush that can't be easily stopped. Robots are not far behind due to their Zerg Rush of weak minions with abilities that summon even more minions and power themselves up. Many playing groups have even banned the combination of Zombie Robots, and some have even banned one or both those factions.
  • Zombies also pair game-breakingly well with Ghosts. Ghosts are all about getting rid of the cards in your hand to unlock special effects, which suits the Zombies just fine, since they can play from the graveyard anyway. Essentially Zombies turn the cost of the Ghost deck into an additional advantage.
  • Wizards are an incredibly solid support faction, as their specialty isn't situational or gimmicky in the slightest. All they do is increase the number of cards you can play in a turn, which literally every faction in the game benefits from, and completely eliminates the weaknesses of Mighty Glacier factions like the Dinosaurs. This can lead to Complacent Gaming Syndrome. Pairing the Wizards with Ghosts might be an exception, as Wizards tend to play best with a big hand and Ghosts want as few cards as possible there. Played properly, you'll cycle through your deck several times, while a regular combination tends to only do this once.
  • Pirates have gained notoriety thanks to their power 2 minion, the First Mate, having become much more dangerous following the advent of +1 power counters and more plentiful power-increasing play-on-minion actions. This is because the First Mate's special ability allows him to move to another base after the base he's currently on scores, bringing every counter and action with him. That means it's perfectly possible to build one First Mate up to 20+ power, or even to build a few First Mates up to 5-6 power each, then win one base after another until you hit 15+ VP and the game ends. Even temporary power increases can prove quite powerful with the First Mate, as they don't lose that power until the end of the turn; i.e., after bases have stopped scoring. It's not unheard of for some Pirate combos to win within a few turns of starting the game.
    • Cyborg Apes are a particularly scary partner thanks to their play-on-minion actions Cyberevolution (+3 power), Juiced Up (+2 power for each play-on-minion action on the minion, including itself), and Shielding (prevents other players' cards from affecting the minion, meaning they can't even return it to hand to get rid of the actions on it). If a First Mate gets a Shielding on it and no one else has a card that can destroy Shielding, the Ape Pirate player just put the game on a short clock. Cyborg Apes have two copies of Cyberevolution and Shielding each, making them more likely to be drawn and allowing them to stack for Juiced Up.
  • Frozen from Disney Edition has a "flow chart" of characters (Sven >< Kristoff >< Anna > Elsa > Marshamallow, Olaf, or Snowgie) who can fetch each other from your deck or discard pile, making it ridiculously easy to assemble them onto a single base. One of their actions, Reindeer Are Better Than People, can fetch a minion from your deck and place it into your discard pile or, if its power is 3 or less, into your hand, allowing you to fetch Sven and thus begin the flowchart combo.
  • Action Heroes are in danger of becoming this, as they can break bases incredibly fast with the right combination of cards. The most straightforward combo is Rambro (-4 breakpoint to the current base if he's alone) + Friends Through Eternity (or another double extra action play like Time Loop or Favor of Hermes if available) into All Out of Bubblegum (+2 power, extra action play if the minion is alone) into Lone Wolf (+2 power, +4 power if the minion is alone) or Collateral Damage (-5 breakpoint until the end of the turn).