These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Character Tiers: Built into the game automatically thanks to the resource meter. The earlier games had a larger system, ranging from four stars to a half star (590 points to 200, out of 1000 per battle). Computer-controlled machines are always worth half their normal value. Of course, the actual tier rankings take a lot of different factors into consideration, including cost effectiveness.
Gundam vs Gundam streamlined the system, setting the resource meter at 6000 points and dividing the characters into three tiers: 3000 points for big names like Nu Gundam and the AU protagonists' Mid-Season Upgrades, 2000 for middle-of-the-road machines, and 1000 for lower-level machines. Extreme Vs adds a 2500-point tier for machines that are just below protagonist level, like the Infinite Justice and Cherudim Gundams (and, for some reason, God Gundam; Master is 3000). Maxi Boost further shakes things up, removing the 1000-point tier in favor of a 1500-point tier and upgrading several characters, like God finally getting brought back to 3000note The real big winner is 00's Arios Gundam, which jumps from 1000 to 2500.
Development Hell: It took a long time for Gundam AGE to finally make it into the series. Although Gundam 00 and Unicorn were quickly represented in the Gundam Vs. Gundam NEXT series, AGE's represenative (AGE-1) was originally a planned DLC unit for the Playstation 3 version of Extreme VS., but given how the franchise was viewed by the fanbase as a Franchise Killer, AGE-1 and the series in general had to wait until Maxi Boost before they could finally make their debut, 2 years after the series ended.
First Installment Wins: The original series gets more characters than any other series in Gundam vs Gundam NEXT, even if some of these inclusions are questionable (Guntank? Acguy?)
Inverted with Extreme VS, which gives the most recent series (00 and Unicorn) a disproportionate number of mobile suits and characters, and added even more via DLC and in the Full Boost arcade sequel. Though granted, older series are starting to get a similar treatment with each new DLC in Full Boost. In fact, the ZZ roster gets the blessing from the DLC as this brings the list from 4 to 8 (Mainly since this brings in the other ZZ pilots and the Zeta Zaku).
Goddamned Bats: Guntank. Weak, cheap (1000BP), bad at melee. It's main weapon are twin long range cannon. Normally this is not a big problem. But Guntank carries 30 ammo, making to quite hard to takedown even using 3000BP melee based mecha. Better work on your boost management or prepare to get bombarded.
And Zeong's head on last leg mode. Can turn your possible victory into frustrating stalemate because it's speed and small size.
Extreme Vs. has the Hildolfr, which inherits the Guntank's annoying cannon sniping and combines it with a couple of melee moves and smoke dischargers that cut your attacks' tracking on them. It was considered such a Game Breaker that it received a severe Nerf in the transition to Full Boost.
Good Bad Bugs: The SEED games introduced Green Homing: When an enemy machine is near you, the targeting recticle turns red and certain attacks (beam rifles/cannons, missiles, etc) get improved homing; when they're far away, the recticle turns green and they're harder to hit. Green Homing occurs when you fire while switching targets from a distant enemy to a nearby one, giving the improved homing to a long-range attack and letting you pull off some insane tricks.
Poor Man's Substitute: One route in Universal Century Mode allows you to recreate Char's Counterattack, only without any of the machines or characters exclusive to it. This results in Char running around in Puru-Two's Qubeley Mk-II, and Amuro using whatever the player chooses (though this route does unlock a ZZ Gundam for him).
That One Attack: You'd better get used to being hit by Dragon Gundam's Houka Kouten Jyusetsujin, because the AI-controlled Dragon loves using it. The initial rush has auto-guard properties, and if it connects you'll be eating an unfair amount of damage. By the way, be very careful if you try to rescue your partner from this move, since the fire will hit whether or not you're in the flag trap.
That One Boss: The Alpha Azieru, thanks to the fact that it has two different rapid-fire all-range weapons, and absolutely LOVES using both of them on you at the same time and following up with its mouth beam cannon while you're still reeling. Made all the worse by the fact that you have to listen to Quess giggling and mocking you as she spams you to death. The Apsalus III as well, thanks to its hard-to-dodge, highly damaging beam sweep and the infinite Gouf Flight Type assists that keep you from simply getting in its blind spot and hacking it to death with melee.
Extreme Gundam Tachyon Phase, Extreme's melee form. You would think that since it's melee-themed, all you have to do is get at a distance and shoot, right? Wrong! It can hit at insane ranges thanks to its Sword Beam, the Extreme-standard "giant elemental pillars" attack (in this case lightning), and a high-speed dash that lets it quickly close the distance. On top of that, it has sword Attack Drones and can grow its Tachyon Slicer to sizes that would impress Sanger Zonvolt himself. Oh, and if it ever manages to hit you with its shockwave sphere attacknote Protip: The "tell" is holding the sword in front of its face, you will eat a very painful ten-hit sword combo that will rip right through your HP.
That One Level: Next Plus's Mission Mode has a stage where you only have one hit point and are forced to fight Kamille's Mk-II and the Hyaku-Shiki (both possessing Revival abilities) and on top of this, you're on a tiny platform in the middle of a volcano; one misstep and you're dead.
In Federation vs. Zeon's Mission Mode, the Federation has a stage where you have to prevent Zeon from stealing a Gundam. In this mode, however, the Gundam is absurdly powerful, meaning that one or two beam rifle shots is probably enough to kill you (unless you're also in a Gundam, which you probably aren't). In AEUG vs. Titansit gets even worse with a similar stage, except that this time you're facing off against two Zeta Gundams at the same time (one with the beam rifle, one with the mega launcher).
Federation vs. Zeon also has the opening battle for Operation Odessa on the Federation side. You have to defend a Big Tray from waves of Zeon mobile suits. The Big Tray is seriously unprotected - so much as one hit from a Zaku's Magellan cannon takes a fifth of its health away. Even worse if you brought a beam rifle, as it will pierce through the Goufs trying to slice it up and deal friendly fire.
Extreme Vs brings to the table several missions: one where you fight three Exias, two 00 Gundams, and then three 00 Quantas all in one stage, with barely enough time to kill them; one where you have to fight three Destroy Gundams at once; and one where you have to take down both the Turns and the Rafflesia in less than 30 seconds. The worst though is probably "Vs. Gundam (2)": in one life, without skills, and without a partner, fight a Double X and God Gundam tag team, then take on the 00 Quanta, Turn A, and the Destiny all at once.
Pandering to the Base: Let's be honest: by Extreme Vs., the series has become a serial offender due to all the incredible amounts of fanservice. And despite or perhaps in light of that, it works.
The Problem with Licensed Games: Mostly averted; even X-Play gave Federation vs Zeon a positive review. However, the same couldn't be said for Gundam vs Zeta Gundam, which Adam and Morgan found impenetrable to non-fans and too similar to its predecessor gameplay-wise. While the Extreme Vs games have been well received even in Western import reviews; Kotaku even described it as being the best video-game adaptation of an anime franchise to date.
Tier-Induced Scrappy: The Launcher Strike and Strike Noir are banned from Alliance vs ZAFT tournaments because they're so powerful. Launcher because of its exceptional ranged ability (further enhanced by Green Homing) and the fact that the anti-ship vulcan can be used to cover its landings, making it virtually untouchable. The Strike Noir is out because it's a Lightning Bruiser of the highest order.
Gundam vs Gundam gave the Freedom Gundam an ability called S.E.E.D., that let the player instantly cancel whatever he was doing, providing insane combo opportunities and elevating Freedom to God Tier. In Next, the ability (now called Next Dash) is made part of the basic game engine, while Freedom's ability becomes a miniature Awakening. Extreme Vs scales Next Dash (now Extreme Action) back even further by removing the ability to use it during melee combos.
Extreme Vs Full Boost had Wing Zero TV Version, which had a good tracking for its Twin Buster Rifle as its main weapon, then had for its Charged Attack a buff that replaces the main weapon with a full firing TBR. That charge shot fills up fast and catches units who surge towards the WZ. Then come the spread shooting wing vulcan for its sub weapon, the rolling buster rifle attack, and the ZERO System—a timed buff that cuts tracking to the WZ. Many players have utilized its weapon set and overpowered their opponents, until the Nerf updates within the next months which lengthened the time for its Charged Attack and the rolling BFG attack, then reducing the ammo count of the spread vulcan from 90 to 60, and reducing the hitpoints of WZ from 650 to 620.
Before that however, was Unicorn Banshee. A faster NT-D reloading than Banagher's Unicorn and a permanent NT-D advantage when its HP is half of its full health or less, insane melee advantage, and two ammo counts for its beam saber throw, which has an incredible cone range that traps enemies who do not have good reflexes to dash backwards. Even if it did, Banshee can just fire the Armed Armor BS. It was so initially overpowered it was nerfed at the following months: It's HP decreased from 640 to 600, then reducing the ammo count of the beam saber throw to only one, then tightening the permanent NT-D by dropping the HP requirement from half of its max HP to 240. Even today, after many nerfs it still sits at the high tiers for its cost.
Also in Extreme Vs. Full Boost, the Epyon, despite being a melee only unit, can tear practically any mobile suit once it gets close. It's lightning quick attacks can take a huge amount of health out at once, and with it's Bird Mode and other maneuverability, it can close the gap horrifyingly fast. The only saving grace is that it's a 3000 cost unit. This is an interesting example however because some say the opposite, that it's so useless that it isn't even worth using.