do u actually play for 100 hrs or is most of it afk?
depends how you get rank 20 and what games you own. if you only have 1943 (the free game), you can't afk 100 hours and it takes about 350+ hours of game play for rank 20.
if you have other games you can afk 100 hours and get rank 20 a lot quicker.
Give Honor for the first time - Gems of War
Defeat 50 Towers in a single Invasion event - Gems of War
Get your first collectable. - Battletoads