I am testing with the latest nightly build.
You should use the latest nightly build too.
You should remove "Scripts/02 ActorDef.lua" from your theme because that is part of _fallback and including it in your theme causes problems.
On ScreenSelectPlayMode:
WARNING: Lua runtime error parsing "ScreenSelectPlayMode::ChoiceNormal": [string "ScreenSelectPlayMode::ChoiceNormal"]:1: attempt to concatenate a nil value
This occurs because GetGameInformationScreen() does not return anything if the "ShowInstructions" preference is false.
So none of the options on ScreenSelectPlayMode do anything.
Fix GetGameInformationScreen() to return the name of the screen that should be used when "ShowInstructions" is false.
On ScreenGameplay:
WARNING: Error playing command: /Themes/DRAGON NEST THEME/Graphics/Player combo/default.lua:25: calling 'visible' on bad self (boolean expected, got nil)
This occurs because I haven't set that preference, so it's neither true nor false. "ThemePrefs.Get("FlashyCombo")" returns nil. Nil is not a valid boolean for most functions.
You can fix this by using this line instead of what you have:
local ShowFlashyCombo = ThemePrefs.Get("FlashyCombo") or false
On ScreenEvaluation:
WARNING: Lua runtime error: /Themes/DRAGON NEST THEME/BGAnimations/ScreenEvaluation background/AorA-/default.lua:31: Anuarendel Gateway 16-10: not found
Your speed mod line is the worst example of how to provide a wide variety of speed mods. 228 is way too many. If you're going to copy 03 CustomSpeedMods.lua from _fallback into your theme, you should at least use it. (CustomSpeedMods is also not a very good solution, but it's better than 228 options to scroll through, and the better solution is only available in nightly builds)
The load times for each screen are too long.