Thanks for sending me this project.
Although De4dot doesn't find any known obfuscators to have been used in this assembly, the decompiled code itself looks much like obfuscated -- type names, variable names, code organization and so on. Files that JustDecompile misses to produce in project generation are for types that have been marked with "CompilerGenerated" attribute, which happens only for special language constructs which are translated to compiler-generated code and this doesn't seem to be the case here.
Rather unfortunately, despite trying to handle every imaginable corner case, decompiling obfuscated assemblies is not a top priority for us.
Please, do not hesitate to contact us if you stumble upon any other problem.