Executable files and the updated core - _NCF_GLOBAL_ - is a .rar archive (contains NCF__Core.rar [updated core], NCFMegaPackInstaller.rar, H5_Game.NCF.rar, and H5_MapEditor.NCF.rar) - so after downloading, you just need to change the extension from .avi to .rar - extract it and place the contents into the game folder - bin (H5_Game.NCF.exe and H5_MapEditor.NCF.exe) and data (NCF__Core.pak); NCFMegaPackInstaller.rar - if I remember correctly, this is simply an automatic installation of the files H5_Game.NCF.exe and H5_MapEditor.NCF.exe into the game's bin folder.

The new link to NCF_Mega-Pack (25.10.2014) is a .rar archive (contains NCF_MegaPack.pak, NCF_MegaPack-RussianTexts_29062009.pak, and NCF__Core.pak [old core]), so after downloading, you just need to change the extension from .avi to .rar - extract it and place the contents into the game folder - data.