Certain genres are perfect for mindless time-killing as you cleanse your pallet between deeper games. They don’t have to be perfect — they just have to be functional, and moreover, fun. You have expectations going in, adjust accordingly, and can get a whole lot out of a whole little with the right mindset.
The twin-stick shooter is genre is one such example. And man, even with lowered expectations and the right mindset to just sit back and play a mindless game, I still had a hard time really getting into State of Anarchy: Master of Mayhem.
Source: Destructoid Review: State of Anarchy: Master of Mayhem