help to organize myself how to platinize it

[XEXU_DEMON_X10 27]

I'm about to finish platinum for ninja gaiden 3 and 2 I think I'll be able to do it too but I have a lot of doubts with ninja gaiden 1 it's my favorite ninja gaiden too bad on ps3 that wasn't listed I'll try to do the ps4 one can someone recommend me how to start They told me that the best way to go fast would be to reach a boss and unlock the next difficulty but I think I will go from difficulty to difficulty to improve tell me advice please regards community