I don't know how long (wasn't tracked at the time) was the longest among them, but all of the following are easily above 100h, some probably even above 1000h:
PC:
Supreme Ruler 2020
Hearts of Iron III
Victoria II
Fantasy General
The Settlers
The Settlers II
Battle Isle III
Civilization IV
Sid Meier's Alpha Centauri
Eador: Masters of the broken World
Baldur's Gate
Consoles (including handheld):
Dragon Quest VIII
Dragon Quest Monsters Joker
Super Smash Bros Brawl
Mario Kart Wii
The Legend of Zelda II: The Adventure of Link (damn that great palace and it's approach!)
Tetris
Soul Calibur III (and damn you, memory card erasing bug!!!)
Smartphone:
Hay Day
Dots Hero II
Wicked Lair
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454 List as Google Doc: https://docs.google.com/spreadsheets/d/1aW2hXQT1TheElVS7z-F3pP-7nbqdrDqWNTxl6JoJWBY/edit?usp=sharing
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/
Free Pc Games thread: https://gamrconnect.vgchartz.com/thread/248138/free-pc-games/1/
