Revised junctions
The junction effects have undergone a huge overhaul to accommodate other mod changes such as altered spell availability, increased gains from weapons or natural stat growth (see further below). Major downgrades are mostly found in the HP and Speed areas, as it's easier to abuse Limit Breaks with high HP and with too high Speed, the ATB bar just fills too fast for enemies to keep up with the party. On the other hand, some spells have been made better on certain stats, and you can now junction more spells to Elemental Attack and Elemental Defense.
Triple Triad, Card Mod and Refine Abilities
As the gameplay imbalances of Final Fantasy VIII first and foremost stem from the possibility to get strong spells very early by playing Triple Triad, changing the Refine results was an absolute necessity. While you can still benefit from refining cards right after the beginning of the game, it is no longer possible to achieve power levels comparable to the original game: Tents no longer refine into Curaga, the Quistis Card refines into something different than Samantha Souls and the method of acquiring the Zell card has changed. In addition, the earliest you can win Level 6 and 7 Boss cards from card players has been delayed to later stages in the game, as these still hold some of the greater rewards.
Spell power
Some spells that normally don't inflict any damage have been given an attack value. For example, Break is now an earth-elemental spell, and Pain inflicts some Poison damage in addition to its status effects for a greater elemental representation in the game. Most offensive spells are now about twice as strong as usual to make them actually worth casting. To further encourage spell usage, the insanely high spirit stat of some enemies has been lowered. On the other hand, enemies now have the same magical damage output as the party, so they are capable of dealing high spell damage as well.
Damage limit
The 9,999 HP damage limit has been removed for all attacks and the new limit is 60,000 HP, mainly to increase the incentive to use standard physical attacks and GF more often in the late-game. This change includes Gravity based attacks as well, so they are now extremely useful on enemies that have high HP, such as Malboro, Snow Lion or Iron Giants. To prevent Gravity attacks from becoming too powerful overall, it was necessary to make a few more enemies immune to them, or give certain bosses that are vulnerable to it a massive HP boost to compensate for the change.
Limit Breaks
In Squall's case, the base power of each Renzokuken slash and Lionheart have been lowered. The same goes for some of Zell's and Irvine's attacks; also, their time limit to perform attacks has been reduced. Rinoa's Invincible Moon has been replaced and Pet Pals magazines are usually first found at certain locations rather than being available at Pet Stores right away. All of Quistis' Blue Magics have received a major buff, and most of them can break the 9,999 HP damage limit if her Magic stat is high enough. Shockwave Pulsar can deal up to 60,000 HP damage instead of the former maximum of around 30,000 HP. Selphie's Slots benefits a lot from many spells not being available early in the game anymore. In addition, Fire, Blizzard, Thunder and Cure have been removed from the Slot selection entirely and two new Slot exclusive spells have been added.
Rinoa's Angel Wing
The Angel Wing damage multiplier has been reduced from 5 to 4, so using this Limit Break still has an advantage over just casting Triple spells. Furthermore, spell determination no longer depends on what spells Rinoa currently has in her inventory. Instead, the spells she uses are now randomly selected from a set table that consists of only higher tier spells, with different probabilities for each spell.
Aura availability
Aura has been replaced with a new late-game spell that casts Protect, Shell and Regen on one character. Aura Stones are still in the game with their effect unchanged. However, they are very rare throughout the entire game and only a few can be found as a reward for completing sidequests. Aura Stones can still be won through item refinement, which requires a fair amount of grinding though.
Enemies in general
Enemies have been changed in many aspects, ranging from different stats, item drops and drawable spells to even new attacks being used in some cases. Tweaks to the enemy AI have been made as well. For example, enemies now skip their turns less frequently, may use other attacks, switch attack patterns earlier than they usually do and generally act smarter when it comes to self-healing and applying status effects on themselves or the party. The number of enemies immune to Gravity and LV UP/Down has been increased and some enemies are immune to the Vit 0 status effect.
Enemy levels
All enemies are now at fixed levels, to encourage leveling up and to keep perceived difficulty more constant over the course of the game. Enemy levels will gradually increase as the game progresses, so a Bite Bug that is fought in the final dungeon will be at a higher level than the Bite Bugs encountered on the Balamb Isle. Enemies inside Lunatic Pandora are no longer at Level 1, and the level of enemies in the final dungeon is no longer random.
Enemy formations
Many rather pointless encounters that consist of only 1 Geezard or 1 Bite Bug have been altered. Enemies now appear in larger groups more often to encourage GF and spell usage. In return, most enemies drop less EXP to avoid reaching Level 100 too fast. Enemies that you wouldn't normally encounter if you simply follow the main storyline, such as Chimera or Hexadragon, are now included in storyline encounters.
Character base stats
The natural stat growth of all characters has been altered (increased in most cases) to make them more distinct from each other and to make game progress less dependent on junctions. Rinoa now excels even more in Magic Power, Zell in Strength, Irvine and Kiros in Speed and so on. There are only few exceptions in which a character stat growth is lower than normal, most notably Zell and Ward when it comes to their Magic and Spirit stats (as high HP and Strength require an appropriate penalty).
Weapons
The gain in Strength deriving from weapons has been generally increased. Especially the jump from a character's second best to best weapon is now much more noticable than before. As a compensation, the materials needed for upgrading a weapon may be different and usually harder to come by than the materials you normally need. Other than that, the base power of each Ultimate Weapon has been increased. This value works independently from the bonus they add to each character's Strength stat, so a standard physical attack performed with an Ultimate Weapon will always inflict more damage than all the lower tier weapons, even if the character is already at 255 Strength.
GF
Every GF's Ability list and Compatibility values have been altered. Some Abilities now require a different amount of AP to learn. Items that increase Compatibility to a GF have been given a boost and no longer decrease Compatibility of other GFs. The Boost Abililty is currently not available as it is planned to be replaced with a new Ability in a possible revision of the mod. As a compensation for the missing Boost Ability, the base power of all GF that inflict damage has been increased. Drawable GF can no longer be missed and will be automatically added to the player's inventory after beating the respective boss. It's still possible to draw all the GF in question though, and doing so will grant the party a certain advantage in battle, while beating the boss without drawing the GF will be rewarded with some extra items.
Summoning Odin
Odin summon mechanics have been changed in a way that he no longer interrupts battles randomly, and is now summoned by using an item called Amethyst instead, to avoid his often unwanted occurrences. After defeating Odin at Centra Ruins, the player receives 10 units of this new summon item, and 3 more each time Odin's chamber is visited again after all Amethysts are used up. There is no other way of getting this item, so the maximum amount the player can carry at the same time will always be limited. The idea behind this change is adding another resource management element to the game, and of course also to make getting Odin more worthwhile. To keep Odin and Gilgamesh mutually exlcusive, the latter can be acquired only by completing disc 3 without any Amethysts in your inventory, which results in Odin no longer appearing at Centra Ruins to give the player more Amethysts.
Ability adjustments
The gain from Abilities such as HP+40% has been reduced. The damage multipliers of Angel Wing, Darkside and Kamikaze have been altered. Characters now take more damage when using Darkside. More enemies can be devoured for stat boosts, including two new outcomes. Return Damage is available early in the game and has been improved. Step Mine/Traveler, known from Final Fantasy VI and XII, has been added as a new Command Ability and inflicts damage based on steps taken to all enemies. The Absorb Command Ability has been replaced with Heal, which restores HP to all party members equal to 18,75% of their max HP. The Doom Command Ability inflicts some magic damage in addition to causing the Doom status, while Treatment restores some HP in addition to curing status changes. The Rare Item Ability has been fixed so that it is possible to obtain Items from an enemy's steal/drop slot 4 with a higher probability than without Rare Item.
Drawing spells
In battles, the draw cap of 9 has been lifted to a theoretical 100 units per Draw. Draw Points may contain different spells than usual, or change their contents over the course of the game. Some have been made invisible or previously invisible ones visible. Some Draw Points that normally refill no longer do, or vice versa. The maximum amount of spells drawn from a single Draw Point has been increased in most cases.
Sidequests
Several rewards for completing sidequests have been improved (especially the treasure found in Chocobo Forests). Certain NPC interactions that previously went unrewarded are now being rewarded with items, and on top of that, some new sidequests and challenges have been added to the game.
New Items
Hero-trial and Holy War-trial have been removed from the game, and a few items have had their effects condensed in order to create space for several new items usable in battle.
Other changes
A new Shop that allows for buying several items that turn into spells can be accessed in Deling City, further alleviating the tiring process of acquiring spells. Chocobo World loot has been rebalanced in a way that some items (such as Ribbon, Dark Matter or Solomon Ring) have been omitted from it completely, while others are still in, but have had their probability reduced (Friendship, Stat Up items etc). The mod also features a SeeD salary rebalance, options to abolish card game rules in every area, added effects to GF summonings, some new scripted enemy encounters where you wouldn't necessarily expect them, and quite a few other changes not listed here to leave some surprises.
