Serious Sam 4
54 Achievements
15-20h
GOG
Holy Driver
Ride the Popemobile to victory.
22.3%
How to unlock the Holy Driver achievement in Serious Sam 4 - Definitive Guide
You will get this achievement upon the completion of the mission "Machina ex deus". You will end the mission fighting a massive boss, just keep shooting it in the face until it closes and then mob the area (Kill all enemies) and it will re-open for you to finish it off. To make this easier make sure you have infinite ammo turned on and even tourism difficulty or play on co-op and set respawn timer to 0.