Welcome back
Drive: by equipping these you unlock a secondary pool of level-up abilities (cartridges). They come in three flavors: boost (mainly augments flight time and it's recovery), sword (adds special effects to melee attacks) and armor (adds to your units survivability). There's a guide for them. You can check the available cartridges before equipping them to any bot. Be aware that you can not gain "normal" levels, once you equipped a drive. You can still reset your cartridges and use custom dashes (air loop etc) though.
UC is won in arena, missions and quests. You can fulfill treasure collections (Arcantus) in quests to gain a UC reward, these quests reset every week, along with the maps in Arcantus mode.
We also got "core tunes" which add special effects to your bots (longer Wonder Bit duration, ammo regain when stunned, etc). You can check and apply them in the cosmos capsule. Unlike other tunes these will always succeed, but have a chance to be a "Great Success", meaning that the effect is even better.
Generally, we've got a lot of new stuff since LRE.
Repair Bits are dead: healers will now use "weapons" to regenerate ally HP whenever they want.
People will hardly use LND gunners anymore.
Almost everything uses aphastrikes now (one of the core tunes allows you to shoot for a longer time).
Expect homing bullets everywhere.
Most bots will use a debuff or two.
We can now receive more buffs at once.
We got moefied versions of Fractulus and Berzelius, the latter is an ART unit who can extend her fly time.
Melee is way safer to use now, most of the attacks are good enough to chase your targets even if they are flying.
Some of the ranged subweapons will now feature melee-type attacks, meaning that they will always stun (Lumiera is famous for that).
Some bots have special wonderbits that are connected to a subweapon.
Sometimes these bits are on demand AURA functions.
Sometimes it is a lockon-subweapon that will cause the bits (or parts of them) to follow the target ("Pursuit Bits").
The charakter Rouche will install a "Barrier Bit" that generates a huge energy field to bock projectiles.
Lumiera and Medi Aide ANGEL will install a shield, very much like the Barrier Field item, these bits will also buff allies (Lumiera gives long range) and debuff enemies (Lumiera's shield gives Slow turn, or Powerless, Medi Aide's cause shock)
And then there is Chloe Pepperomia whose "phantom floor" is a hovering platform that buffs allies and can't be damaged by ranged attacks.
New tunes were added and one or two got changed to be more useful.
Eternal used to be a 50 cost tune that prevents the part from breaking, now it is 25 cost and adds 15 HP along the unbreakable effect.
Revenge tunes are special effects that are randomly triggered, when the unit gets stunned. Hypershot is hardly ever use, Clearance cancels debuff effects, Crimson Veil makes you ignore additional stuns. All of the revenge tunes will also activate All Guard.
EX tunes are like normal status tunes, but also add HP. Their success rate is way lower, they take more UC (a LOT more) and you need special tuning materials known as "elements" to do them.
Expect the average player to have somewhere between 500 and 700 HP. Some people run builds with even more (1000 HP is possible).
The black-haired girl from Lily Rain's vision got released as a playable unit, her name's Eve.
A new type was added: ZERO types may chose between two different cartridge pools and then gain 12 levels. Their built in attacks are dependent on their special cartridges though, so it's more or less the same as having 10 levels. Eris and Resha were the first units to have this type. In battle they will act like a different type though: Eris and Resha a both marked as "LND" types (beam weakness and LND mobility), but we also got AIRs (Eve and Alcy Rivette), SUPs (Eris and Resha in waitress attire) and even an ART (Kougetsu Kagura). There're some more ZERO types.
Some units will use a "mark-shot", if an enemy gets hit by them, a different weapon of the same unit will become more effective (Alcy Rivette and Vanessa Batros will use their markshots to gain a buff with their other weapons, Rosso Aspide can use his to steal boost time with his core weapon, etc).
We got more male charakters than Jikun Hu now, but they're still a rare sight (Eve's friend Jace, Dracken and Lios' humanoid versions and the henshin hero Leon aka Astralyzer).
Emote animations were added: press the asigned button and then one of the number keys.
Some charakters are "Extra Origin" versions and get additional animations.
Many charakters will now talk during their attacks, even is they're using a mainweapon.
We often get delight tickets now: they can be used to roll "Delight Garapons", normally there's one with older units and one that is a copy of the feature garapon, the latter takes more delight tickets per roll though. Note that you have to pay the full price for 5x rolls in the delight versions.
Sometimes we're having events in which you can collect special cards based on your score-ranking. The prizes will include stuff like Slot Protectors, or even Deluxe Coins which can be exchanged for bots.
Every month one can buy up to 50 Rt with UC now. The first 10 will be 700 UC each, then 1400 UC, then 2100 UC and so on. You can find the UC>Rt "item" in the item section of the shop. Drive items will reset in the same manner.
Mmh...I think I forgot some stuff, but oh well. I'm an incompetent scrublord anyway~
Five years is a long time, okay?! I-It's not my fault if you keep playing this long!
 anyway you can ask me for help . 
