Forget peaceful and relaxing games. Here are some co-op titles that will test the skills and tempers of all gamers.

Some co-op players choose unhurried gameplay. They like relaxing, zen-inspired games that don't spike heart rates or demand quick reflexes. Such casual players are not the target audience for this article.

This list of games is for co-op players who enjoy a real challenge, who need to be tested and perplexed, and who are prepared to face failure or frustration in order to get their gaming fix.

The games listed here are all top-notch in and of themselves, yet they may all be stressful in various ways. But only the determined will find the big reward.

This is a cooperative work of art. The gameplay is also filled with absurdity and inane comedy, which permeates the entire game.

This game features two different ways of stress. First of all, as the game progresses, the environments get much more difficult, and players will need to work together very well due to the tight timelines.

Expect to restart levels many times. 

Expect to restart levels many times.