Doom (stylized as DOOM) is a series of first-person shooter video games developed by id Software. The series focuses on the exploits of an unnamed space marine operating under the auspices of Union Aerospace Corporation (UAC), who fights hordes of demons and the undead in order to survive.

Based on that paragraph can we conclude that this sentence is true?
The DOOM series is id Software's most successful product.
It's impossible to say