Restored Behavior

• BuildCraft-style "piston" engines now explode like they did in 1.2.5, either from lack of coolant or from trying to generate power with nowhere to send it
• BuildCraft conductive pipes now have distance-based losses like from 1.2.5
• BuildCraft gold item pipes require redstone signals again
• Restored old fluid side input rules on BC refinery
• BC Wooden/Emerald pipes once again only take power from engines or gates, not ducts or other power conductors
• Project Red renamed to Redpower in Waila and NEI
• Electrotine Ore renamed to Nikolite, and uses RedPower World textures
• Illumar renamed to Lumar, and uses old RedPower recipes
• IC2 Hammer and Cutter now use sticks and cobblestone, like in 1.5.2 and prior
• Eliminated 1.4+ zombie behavior (sieges, door-breaking, calling for help, long-sight)
• Eliminated baby zombies
• TE Tesseracts have a 25% loss in RF transport again
• Forestry alvearies once again have a 10x yield bonus

Mobs

• Several mobs wil not spawn
  • Bats and Witches will not spawn naturally
  • Blitzes and Basalzes will not naturally spawn
  • Pechs and Eldritch guardians will not spawn
• Toned down advanced AI on hostile mobs
• Skeletons now have pre-1.4 fire rates and arrow damage
• Cave Spiders give poison, even on Easy difficulty
• Cave Spiders from Mineshafts drop Torchberries
• Endermen can no longer pick up blocks
• Disabled baby heatscar spawn on heatscar death
• Sheep now regrow wool faster
• Blue Slimes will not spawn in the Twilight Forest
• Halved angry zombie spawn rate

Visual

• More appealing BoP biome grass/foliage colors
  • Less brown and more green, and richer greens rather than gray-green
  • Affects Jade Cliffs, Seasonal Forest, Orchard, Shield, Temperate Rainforest
• Carpenter's Blocks now do not render shared sides, to avoid issues with semitransparent cover types
• Carpenter's Blocks now use location-specific textures for their cover blocks
• Forestry leaves now are properly tinted by biome color
• Immersive Engineering Diesel Generator sound is deeper and more substantiative
• Computronics lamp now has a halo and nicer glow visuals
• BetterFoliage round logs have improved side connectivity logic
• ThaumCraft aspect list overlays (eg nodes) now has a configurable row length
• Very large TC nodes no longer render dozens of blocks across
• Thaumic Tinkerer Camo blocks now do not render shared sides, to avoid issues with transparent cover types
• ExU drums now make metal sounds when hit, pitched to the fill level of the drum
• New botania livingrock texture
• Gadomancy mirrored jars now have a shorter "pot" to better show the jar label
• RailCraft force tracks now emit light
• Low Y levels in the nether now have a heat shader
• TiC clear glass now merges sides with smeltery glass
• Pane-type blocks (eg iron bars) now connect to facade blocks

Theming

• Added custom main menu
• Botania color items (eg flowers) now use ChromatiCraft element names (eg Karmir Petal instead of Red Petal)
• ThaumCraft mana bean eating now gives potion effects based on which ChromatiCraft crystal elements are required to fabricate that aspect
• Twilight Forest portal is now opened with Torchberries
• EiO conduit networks now gradually drain RF, 20RF/t base, more if the network is far from completely empty or full
• IC2 refined iron fully isolated from oredict steel
• Diamond conductive pipes are now a variant of gold conductive pipes, and resemble them visually to better fit 1.2.5-era BC styling
• All Forestry trees and butterflies now have an associated climate region, and leaves will only spawn appropriately local butterflies
• Radioactive ores now give very weak radiation effects to nearby entities

Misc

• BoP Loftwood can once again be planted and grown
• AgriCraft crops and Botania flowers are now flammable
• Ghast spawn rate increased substantally
• Diamond nugget from Translocators replaced with 'Translocator Control Circuit'
• MeteorCraft meteors (and AE by proxy) only spawns in the End
• OpenBlocks elevators use 1 XP per meter
• Trees now occasionally shed saplings which last for 10 seconds
• Aspect Orbs do not drop
• BoP pinecones can now be placed
• EiO XP Boost Enchant changed to item type "weapon"; now works on unbreakable weapons, but no longer works on mining tools
• TiC tools no longer are invicible or infinite-life if dropped
• Growthcraft apple cores are now obtained by eating apples
• Music categories shuffled, allowing for a larger music library you actually hear
• Reika given custom TC aspects
• Certus bee now is bred from quantum rather than silicon
• Boggy bee now produces moss instead of peat
• Removed king slime tool drops, but added clay balls
• Oak trees planted in BoP rainforests can now spawn flowering oak leaves
• TC aspect bubbles now pass through blocks

HexCraft

• Custom monolith generation algorithm
• Spamming generators now greatly penalizes efficiency
• Hex Generator now has variable burn time and emission rate based on fuel type
• Greatly expanded and revamped Hex Generator fuel set
• ChromatiCraft Adjacency cores now work on the energy generators and chunk loader
• Quantum observers now share one global energy pool
• Quantum observers now have a custom AoE and power consumption curve
• Hex Crystals can now be multiplied using lava and obsidian recrystallization