Putting this up to gauge interest before committing a large amount of time to it. It's fairly bare-boned in its current state. Currently, this is best used for multi-classing. The higher levels mostly only contain extra resources such as spell slots, sorcery points, rage charges, etc.

The idea behind this mod is to allow players to gain the features of levels 1 through 20 while still maxing out at level 12. There are a couple of reasons I took this approach:

• I'd like to keep the game a little more balanced. Adding 8 more levels worth of HP dampens the sense of danger you are in. I tried to resolve this in a separate mod that reduces the amount of HP gained per level, but that led to unforeseen complications.
• Parameters set by the LevelMapValues.lsx (cantrips, proficiency bonus, rage damage, sneak attack, etc.) don't seem to be recognized by the game if they exceed level 12.
  

The current progression for each level when it comes to gaining features and resources is as follows:

  Level 1 = Level 1
  Level 2 = Level 2
  Level 3 = Levels 3 & 4
  Level 4 = Levels 5 & 6
  Level 5 = Levels 7 & 8
  Level 6 = Levels 9 & 10
  Level 7 = Levels 11 & 12
  Level 8 = Levels 13 & 14
  Level 9 = Levels 15 & 16
Level 10 = Levels 17 & 18
Level 11 = Level 19
Level 12 = Level 20

Cantrips increase in power at the following levels (showing D&D 5e's 20 level system as a comparison):

D&D 5e Condensed Level System

  Level 1 = Tier 1   Level 1 = Tier 1
  Level 5 = Tier 2   Level 4 = Tier 2
Level 11 = Tier 3 (Lvl 10 in BG3) Level 7 = Tier 3
Level 17 = Tier 4 Level 10 = Tier 4

Proficiency Bonus scales up at the following levels:

D&D 5e   Condensed Level System

  Level 1 = +2  Level 1 = +2
  Level 5 = +3  Level 4 = +3
  Level 9 = +4  Level 6 = +4
Level 13 = +5  Level 8 = +5
Level 17 = +6Level 10 = +6

Spell slot progression has been changed to add more 2nd-6th level spell slots on top of being condensed. I've yet to create 7th-9th level versions of the base game spells, and I'm wondering if I even should since spellcasting is already quite strong. 

D&D 5e  Condensed Level SystemCondensed Level System 0.4

  Level 1 = 2 | 0 | 0 | 0 | 0 | 0  Level 1 = 2 | 0 | 0 | 0 | 0 | 0  Level 1 = 2 | 0 | 0 | 0 | 0 | 0
  Level 2 = 3 | 0 | 0 | 0 | 0 | 0  Level 2 = 3 | 0 | 0 | 0 | 0 | 0  Level 2 = 3 | 0 | 0 | 0 | 0 | 0
  Level 3 = 4 | 2 | 0 | 0 | 0 | 0  Level 3 = 4 | 3 | 0 | 0 | 0 | 0  Level 3 = 4 | 3 | 0 | 0 | 0 | 0
  Level 4 = 4 | 3 | 0 | 0 | 0 | 0  Level 4 = 4 | 3 | 3 | 0 | 0 | 0  Level 4 = 4 | 3 | 3 | 0 | 0 | 0
  Level 5 = 4 | 3 | 2 | 0 | 0 | 0  Level 5 = 4 | 3 | 3 | 2 | 0 | 0  Level 5 = 4 | 3 | 3 | 2 | 0 | 0
  Level 6 = 4 | 3 | 3 | 0 | 0 | 0  Level 6 = 4 | 3 | 3 | 3 | 2 | 0  Level 6 = 4 | 3 | 3 | 3 | 2 | 0
  Level 7 = 4 | 3 | 3 | 1 | 0 | 0  Level 7 = 4 | 3 | 3 | 3 | 2 | 1  Level 7 = 4 | 3 | 3 | 3 | 2 | 1
  Level 8 = 4 | 3 | 3 | 2 | 0 | 0  Level 8 = 4 | 4 | 3 | 3 | 2 | 1  Level 8 = 4 | 4 | 4 | 3 | 2 | 1
  Level 9 = 4 | 3 | 3 | 3 | 1 | 0  Level 9 = 4 | 4 | 4 | 3 | 2 | 1  Level 9 = 4 | 4 | 4 | 3 | 2 | 2
Level 10 = 4 | 3 | 3 | 3 | 2 | 0Level 10 = 4 | 4 | 4 | 4 | 2 | 1Level 10 = 4 | 4 | 4 | 4 | 3 | 2
Level 11 = 4 | 3 | 3 | 3 | 2 | 1Level 11 = 4 | 4 | 4 | 4 | 3 | 1Level 11 = 4 | 4 | 4 | 4 | 3 | 3
Level 12 = 4 | 3 | 3 | 3 | 2 | 1Level 12 = 4 | 4 | 4 | 4 | 3 | 2Level 12 = 4 | 4 | 4 | 4 | 4 | 4
Level 13 = 4 | 3 | 3 | 3 | 2 | 1 | 1 | 0 | 0 
Level 14 = 4 | 3 | 3 | 3 | 2 | 1 | 1 | 0 | 0 
Level 15 = 4 | 3 | 3 | 3 | 2 | 1 | 1 | 1 | 0 
Level 16 = 4 | 3 | 3 | 3 | 2 | 1 | 1 | 1 | 0 
Level 17 = 4 | 3 | 3 | 3 | 2 | 1 | 1 | 1 | 1 
Level 18 = 4 | 3 | 3 | 3 | 3 | 1 | 1 | 1 | 1 
Level 19 = 4 | 3 | 3 | 3 | 3 | 2 | 1 | 1 | 1 
Level 20 = 4 | 3 | 3 | 3 | 3 | 2 | 2 | 1 | 1 

I used a custom XP curve in an attempt at more balancing. Using the vanilla level curve could lead to getting too strong too fast. What I've currently implemented is built off ThinkDM's Revised XP Table. I reduced the XP requirements by half, I then combined the XP requirements of certain levels (3&4, 5&6, etc.) to match the condensed leveling structure, and finally tweaked it for further smoothing of the progression. It is intentional that the custom and vanilla tables stay pretty close up to level 6. I found that the mid-end game is where difficulty started to wane in my playthrough, though I'm open to feedback on that.

Baldur's Gate 3Condensed Level System

  Level 1 =         0XPTotal =            0XP  Level 1 =         0XPTotal =            0XP
  Level 2 =     300XPTotal =       300XP  Level 2 =     250XPTotal =       250XP 
  Level 3 =     600XPTotal =       900XP  Level 3 =     750XPTotal =     1000XP 
  Level 4 =   1800XPTotal =     2700XP  Level 4 =   2000XPTotal =     3000XP 
  Level 5 =   3800XPTotal =     6500XP  Level 5 =   4000XPTotal =     7000XP 
  Level 6 =   6500XPTotal =   13000XP  Level 6 =   8000XPTotal =   15000XP 
  Level 7 =   8000XPTotal =   21000XP  Level 7 = 12000XPTotal =   27000XP 
  Level 8 =   9000XPTotal =   30000XP  Level 8 = 17000XPTotal =   44000XP 
  Level 9 = 12000XPTotal =   42000XP  Level 9 = 22000XPTotal =   66000XP
Level 10 = 14000XPTotal =   56000XPLevel 10 = 28000XPTotal =   94000XP
Level 11 = 20000XPTotal =   76000XPLevel 11 = 36000XPTotal = 130000XP
Level 12 = 24000XPTotal = 100000XPLevel 12 = 45000XPTotal = 175000XP

Update 0.1.1

Updated class progression to include everything added up to Patch 4:

• Updated College of Lore skill selection to be any skills instead of the 3 set in vanilla.
• Multiclassing into Ranger grants Heavy Armor proficiency.
• At level 4, Knowledge Clerics gain Channel Divinity: Read Thoughts, Nature Clerics gain Dampen Elements, and Trickery Clerics gain Channel Divinity: Cloak of Shadows.
• Archfey Warlocks get a cantrip at level 3.
  

Update 0.2

Made a few corrections and adjustments to features/spells that scale with level:

• Bard: Added d12 inspiration starting at level 9.
• Druid: Reverted the progressions table to vanilla regarding wildshape forms. This is likely a temporary measure. Ideally, I'll adjust the starting HP to all forms gained after level 2 to reflect the level they were moved to (Deeprothe moved from 4 to 3, Owlbear moved from 8 to 5, Myrmidons moved from 10 to 6, etc.). In the previous versions of this mod, getting those forms at those levels threw off the HP curve, making Druids more tanky than intended. If I adjust wildshape progression back to 1.0 and 1.1 (reducing starting HP), I'd also like to come up with more forms for later levels so they feel less bare.
• Fighter: Added d12 superiority die for Battlemaster at level 10.
• Monk: Adjusted Ki point distribution to match the intended level structure. Added spell replacement at level 12 for 4 Element Monk. Fixed the following 4 Element spells to scale properly with level: Blade of Rime, Clench of the North Wind, Fangs of the Fire Snake, Flames of the Pheonix, and Sphere of Elemental Balance.
• Warlock: Removed invocations from level 3 (I had accidentally copied the gains from level 4)
  

Update 0.3

Created higher level spell lists for half/third casters, moved level 5 racial spells down a level, and made a few more corrections:

• Fighter, Eldritch Knight: now gets access to 3rd level Abjuration/Evocation spells starting level 8, and 4th level Abj/Evo spells at level 11. I previously used the Wizard 3rd and 4th spell lists for all levels that they gain spells. It's now reduced to match RAW. They can still learn any Wizard spell at levels 8 and 12, as well as replace with any spell at every level. That last part might be a bit unbalanced, but that's how Larian did it.
• Paladin: removed the extra fighting style choice I added at level 3 by mistake. I also realized that I left Oathbreaker as selectable during CC. This was something I was testing and forgot to remove. I figure I'll keep it in there if no one is bothered by it. They now learn 4th level spells at level 8 and 5th level spells at level 10. I made a few tweaks to the oath spells due to the RAW spells missing from the game.
• -Oath of the Ancients gets 4th level spells Ice Storm and Stoneskin (both are same as RAW), and 5th level spells Conjure Elemental and Wall of Stone (both custom).
• -Oath of Devotion gets 4th level spells Freedom of Movement and Guardian of Faith (both RAW), and 5th level spells Flame Strike (RAW) and Greater Restoration (custom).
• -Oath of Vengeance gets 4th level spells Banishment and Dimension Door (both RAW), and 5th level spells Hold Monster (RAW) and Planar Binding (custom).
• -Oathbreaker gets 4th level spells Blight and Confusion, and 5th level spells Contagion and Dominate person (all RAW).
• Ranger: Added missing spell choice at level 3 and missing spell replacement at level 12. I added some extra Ranger spells at 4th and 5th levels than RAW to give them a little more end game power. By RAW, they receive the 4th level spells Conjure Woodland Beings, Dominate Beast (Tasha), Freedom of Movement, Grasping Vine and Stone Skin. I added Conjure Minor Elemental. By RAW, they receive the 5th level spell Greater Restoration (Tasha). I added Conjure Elemental and Insect Plague.
• Rogue, Arcane Trickster: same thing as Eldritch Knight, but with Enchantment/Illusion spells instead of Abjuration/Evocation.
• Wizard: Removed extra spells gained at level 2 when choosing Evocation as your subclass.
• Drow: Moved Darkness from level 5 to level 4.
• Duergar: Moved Invisibility from level 5 to level 4.
• Ginthyanki: Moved Misty Step from level 5 to level 4.
• Tiefling (Asmodeus): Moved Darkness from level 5 to level 4.
• Tiefling (Mephistopheles): Moved Flame Blade from level 5 to level 4.
• Tiefling (Zariel): Moved Branding Smite from level 5 to level 4.
  

Update 0.4

Sorry for the long wait on this update. A bunch of family/friend events + trying to get things to work that don't seem technically possible within the limits of the game + CONSTANT crashes since hotfix 10 came out = a long two weeks. Regarding the constant crashes, I'm pretty sure I need to do clean reinstall. It's been happening with or without mods.

Trying to get the 18th level Druid feature, Beast Spells, to work was a pretty big time sync, and I ultimately pushed it off until later. I don't think there is a good way to implement this feature. I was able to get it kind of working by applying the rules of disguise self to wildshape, but there were still no animations for spells cast while in that form. Anyway, on to the things I could get working!

• Spell Slots: Please see new layout above. Added 1 more 5th and 2 more 6th level spell slots. This is likely a temporary measure as I've begun working on 7th-9th level versions of the base game spells. For now, I've made this as a compromise. You still get less total spell levels than 5e (89 vs 84), but you get more spell slots overall (22 vs 24). Thanks to oktez for suggesting the increase to spells slots!
• Barbarian
  

• Brutal Critical upgrades at levels 8 and 10.
• Persistent Rage at level 9. RAW. Uses the same functions of Endless Rage from Early Access without the psychic damage.
• Indomitable Might at level 10. Not RAW. Gives an altered form of Reliable Talent only for physical skills.
• Primal Champion at level 12. RAW. Increase current and maximum str and con by 4. Rage charges replenish per turn instead of long rest.
• General change: removed the bonus action cost from ending rage. This is mainly to go with Primal Champion, especially if you are playing as a Wild Magic Barbarian and want to change you rage effect. AFAIK, in 5e you can rage while raging, but you can't in BG3. It was less invasive to in-game files to remove the cost of ending rage as opposed to changing all the rage entries so that you can rage while raging.
  

• Bard
  

• Song of Rest upgrades at levels 8 and 10. Not RAW. Created a resource for Song of Rest so that each upgrade adds another use, meaning you eventually can use it three times per long rest. Need to create a custom icon for the resource.
• Magical Secrets at levels 8 and 10. RAW-ish. The level 8 version adds 6th level spells: Arcane Gate, Chain Lightning, Heal, Planar Ally and Wall of Ice. The level 10 version lets you select from the entire spell pool.
• Superior Inspiration at level 12. RAW. Regain a bardic inspiration charge if you start combat with no charges.
  

• Cleric
  

• Divine Intervention 2 at level 12. Not RAW. You can now cast the healing and damage spells from the base Divine Intervention once per long rest.
  

• Druid
  

• ArchDruid at level 12. RAW-ish. Wildshape now replenishes per turn instead of short rest. They also get a free Subtle Spell toggleable passive.
  

• Fighter
  

• Indomitable upgrades at levels 8 and 10. RAW. Same as Song of Rest; extra use from each upgrade. Need to create custom icon for resource.
• Action Surge upgrade at level 10. RAW. Same as Song of Rest; extra use from upgrade. Need to create custom icon for resource.
• Extra Attack (4 attacks) at level 12. RAW. Same effective method as the Extra Attack passive Fighters get at level 11.
  

• Monk
  

• Fixed Harmony of Fire and Water so that it restores half of your Ki maximum instead of an amount equal to half your level.
• Unarmored Movement upgrades at levels 8 and 10. Each upgrade adds another 1.5 meters (5 feet) to your movement.
• Tongue of Sun and Moon at level 8. Not RAW, also not called Tongue of Sun and Moon. They now get Speak With Animals and Speak With Dead, costing 1 and 2 Ki point, respectively.
• Diamond Soul at level 9. RAW-ish. Proficiency in all saving throws. If they fail a saving throw, they can spend a Ki point to reroll, taking the second roll. NOTE: I moved this up one level from where it should be. Monks get almost nothing at level 9 (15&16 in 5e). They still get a feat, but their level 15 feature Timeless Body has no practical use in BG3. It stops monks from aging.
• Empty Body at level 10. RAW-ish. Spend 4 Ki points for greater invisibility. Gain resistance to all damage except for force while invisible. Does not implement the astral projection aspect from 5e.
• Perfect Self at level 12. RAW. Same as Superior Inspiration, except they gain 4 ki points when they start combat without any.
  

• Paladin
  

• Aura upgrades at level 10. RAW. Increases the range of all auras (main class and subclasses) to 9 meters (30 feet). Doubled the movement boost of Relentless Avenger from 4.5 to 9 meters (15 to 30 feet).
  

• Ranger
  

• Vanish at level 8. RAW. Hide as bonus action.
  

• Rogue
  

• Blindsense at level 8. Not RAW. Gain immunity to the blind condition.
• Slippery Mind at level 9. RAW. Proficiency to Wisdom saving throws.
  

• Sorcerer
  

• Corrected the amount of spells they get from level 8 onward.
• Sorcerous Restoration at level 12. RAW. Regain 4 sorcery points when short resting.
  

• Warlock
  

• Eldritch Master at level 12. RAW. Recover all Warlock spell slots once per long rest.
  

• Wizard
  

• Spell Mastery at level 10. RAW-ish. Gain a 1st level and 2nd level spell that function as cantrips.
• Signature Spells at level 12. RAW-ish. Gain 2 3rd level spells that function as cantrips and can only be used once per long rest.
  

Update 0.4.1

Fixed a couple typos I found (missing parentheses and commas).
Removed level entries from Progressions.lsx that are unaltered by this mod to improve compatibility with mods that adjust those levels (mainly levels 1 and 2). It would mostly affect mods like (Insert Class) Unleashed or mods that add subclasses to Cleric, Druid, Paladin, Warlock and Sorcerer.
My other mods

Deadlier Combat - A modular mod used to remove death saving throws, restrict resurrection to only be used out of combat, and/or reduce your party's HP depending on how many party members you have (newer version) or by reducing HP gained per level (old version).
Dungeon Delver Tweaks - Makes a few tweaks to the Dungeon Delver feat so that it functions relatively close to its 5e counterpart.