Причин тому, что игра вылетает при запуске может быть огромное количество.
Попробуйте включить в настройках лаунчера режим отладки.
Перезапустите лаунчер и нажмите кнопку "играть". Сделайте скрин ошибки и отпишитесь.
[17:02:41] [Thread-14/INFO] [Config]: [OptiFine] Version found: E7
[17:02:41] [Loading Screen Renderer/INFO] [Config]: [OptiFine] *** Reloading textures ***
[17:02:42] [Loading Screen Renderer/INFO] [Config]: [OptiFine] Resource packs: Conquest_.zip
[17:02:45] [Loading Screen Renderer/INFO]: Reloading ResourceManager: Default, FMLFileResourcePack:Better Loading Screen, Conquest_.zip
[17:02:51] [Client thread/WARN] [BetterFoliage]: Mod BetterFoliage is missing the required element 'version' and a version.properties file could not be found. Falling back to metadata version 2.0.14
[17:02:51] [Client thread/INFO] [als]: Mod als is missing the required element 'name'. Substituting als
[17:02:51] [Client thread/WARN] [als]: Mod als is missing the required element 'version' and no fallback can be found. Substituting '1.0'.
[17:02:52] [Client thread/INFO] [FML]: Forge Mod Loader has identified 11 mods to load
[17:02:53] [Client thread/INFO] [FML]: Attempting connection with missing mods [mcp, FML, Forge, BetterFoliage, als, CustomSpawner, customnpcs, PTRModelLib, props, MoCreatures, rpgmod] at CLIENT
[17:02:53] [Client thread/INFO] [FML]: Attempting connection with missing mods [mcp, FML, Forge, BetterFoliage, als, CustomSpawner, customnpcs, PTRModelLib, props, MoCreatures, rpgmod] at SERVER
[17:02:55] [Client thread/INFO]: Reloading ResourceManager: Default, FMLFileResourcePack:Better Loading Screen, FMLFileResourcePack:Forge Mod Loader, FMLFileResourcePack:Minecraft Forge, FMLFileResourcePack:Better Foliage, FMLFileResourcePack:als, FMLFileResourcePack

rZhark's CustomSpawner, FMLFileResourcePack:CustomNpcs, FMLFileResourcePack

TRModelLib, FMLFileResourcePack

ecocraft, FMLFileResourcePack

rZhark's Mo'Creatures Mod, FMLFileResourcePack:RedBox RPG Mod, Conquest_.zip
[17:02:55] [Client thread/INFO] [FML]: Processing ObjectHolder annotations
[17:02:55] [Client thread/INFO] [FML]: Found 341 ObjectHolder annotations
[17:02:55] [Client thread/INFO] [FML]: Identifying ItemStackHolder annotations
[17:02:55] [Client thread/INFO] [FML]: Found 0 ItemStackHolder annotations
[17:02:55] [Client thread/INFO] [FML]: Configured a dormant chunk cache size of 0
[17:03:02][FINE][noppes.npcs.LogWriter:71] Thu Jan 10 17:03:02 EET 2019
[17:03:02][FINE][noppes.npcs.controllers.ScriptController:60] Script Engines Available:
[17:03:02][FINE][noppes.npcs.controllers.ScriptController:66] Scala: .scala
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "Loading Screen Renderer"
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "Client thread"
Exit code 1