Sustainable si Gusion upto late game, longest game ko sa kanya is 40+ minutes. That time malakas na mga late game heroes. Advised ko is to always use IMMORTALITY.
Pag late game kasi counter na siya ng heroes like Claude, Moskov which is pagkain mo sa early to Mid.
So better to finish the game as early as you can. Dahil sa Assasin ka, di mo priority mag push pero if may chance try mo magpush. Advise mo din kakampi mo mag segway kahit isa lang. Sa experience ko pag full build na lahat, di ako nag iinitiate ng attack. Inaantay ko din muna magamit nila Skills nila. Pero kung mabilis ka talaga, for sure kaya mo yan till late game.If you've seen Doof ata yun or si Yasue, nakikill nila si Saber sa tower which is counter ni Gusion dahil sa SS. Pabilisan lang tlaga kamay.