It can be easy to forget just how important difficulty is in gaming. If a game is too easy or too difficult, players can quickly lose interest and subsequently put a game down and never boot it up again. This is why difficulty levels are such a common mechanic in mainstream gaming, as they ensure that players of all skill levels can have an enjoyable experience.

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Although most players are happy to stick to normal mode, some enjoy truly testing their abilities and ramp the difficulty up to its highest setting. For some games, this simply provides a more testing challenge, but for others, like the games featured below, it can provide a brutally difficult experience that can often require an entirely different approach to the game.

10 Halo 2

halo 2 keyart

The classic sci-fi shooter Halo 2 may be one of the most beloved FPS games of all time, but that doesn't mean it hasn't been the source of a few broken controllers. Halo 2's Legendary difficulty certainly lives up to its name, as it's still remembered for providing one of the toughest challenges that the sixth generation of the home console had to offer.

Thankfully, Halo 2's Legendary difficulty makes life a bit easier for players by raising the ability of AI allies. However, players will still need to land headshot after headshot to stand any chance of surviving.

9 Civilization VI

Civilization 6 Hippolyta Hero

The iconic turn-based strategy series Civilization has had numerous gameplay and visual changes since its first iteration. One thing that hasn't changed, however, is the punishing difficulty; one wrong move can quickly see the players' cities on the wrong end of a nuclear attack or their Civ falling behind in the technology race.

The franchise's infamous difficulty is taken to a whole new level in Civilization VI on the hardest difficulty setting, Deity. Trying to win the game on Deity makes it essential that players get a great start and make the most of every move while keeping their diplomatic relationships in check.

8 XCOM: Enemy Unknown

XCOM: Enemy Unknown - shot accuracy

From one turn-based strategy game known for its difficulty to another, XCOM: Enemy Unknown is infamous for its perma-death mechanic. Perma-death is an especially punishing feature in XCOM: Enemy Unknown as all of the time and resources spent leveling the character are immediately wiped away.

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The fact that perma-death is a feature of even the lowest difficulty level speaks volumes on how tough Firaxis Games' strategy experience is. The game's Impossible difficulty lives up to its name, proving one of the toughest strategy challenges since battling Bobby Fischer at Chess.

7 Call of Duty: World at War

Call Of Duty World At War - fps view of battlefield

The Call of Duty series' marketing predominantly focuses on its online multiplayer today, though there was a time when the single-player campaigns were just as anticipated and discussed. Call of Duty: World at War's campaign is remembered for being one of the franchise's best, as well as one of the toughest.

Along with having brutally low health and tough enemies to kill, players struggle to complete World at War's campaign on Veteran due to how ridiculously accurate the enemy AI is with grenades. Treyarch seemingly believed that WWII soldiers had NFL quarterbacks training them for battle, as their grenades will be landing on players' laps anytime they duck into cover.

6 The Legend of Zelda: Breath of the Wild

Legend of Zelda Breath of the Wild Link vs Hinox

The Legend of Zelda: Breath of the Wild has become recognized as one of the greatest open-world games of all time, largely due to its open-ended gameplay. Breath of the Wild allows players to flex their creative muscles with its gameplay mechanics that reward players for thinking outside of the box and for using survival instincts.

However, once players load the game up in Master Mode, these survival mechanics no longer become something fun to try out but something essential to progress in the game. Although the game keeps its colorful, cartoony aesthetic, the game quickly turns into a brutal survival challenge in Master Mode.

5 Resident Evil 7

Resident Evil 7 Biohazard - hallway

The main series Resident Evil games seem to be following a rule of three. The first three games used a fixed perspective while emphasizing puzzle-solving and combat. The next three games had an over-the-shoulder perspective and were more focused on action-combat, and now the series has shifted to a first-person perspective, emphasizing pure horror.

Resident Evil 7: Biohazard's Madhouse difficulty manages to make the game even scarier than it already is by making the enemies terrifyingly strong. There is also a mode titled Ethan Must Die, which reimagines sections of the game in a much far more challenging form than even Madhouse difficulty has to offer.

4 Guitar Hero: Metallica

Guitar Hero Metallica - gameplay

It's easy to forget now just how big the Guitar Hero and Rock Band games were when the first handful of titles hit stores. The simple-to-play, tough to master gameplay enthralled audiences and made the games a fun, entertaining way to feel like a rockstar.

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The Guitar Hero franchise's toughest difficulty made players feel like a rockstar in particular, as mastering it took about as much skill as learning an instrument in real-life. Guitar Hero: Metallica is considered the toughest entry in the series, thanks to the band's fast-paced heavy metal tracks.

3 Dead Space 2

Dead Space 2 - promotional image of the protagonist

Electronic Arts' Resident Evil 4-inspired space shooter Dead Space both intrigued and terrified audiences in 2008. Dead Space 2 was released just over two years later and is today recognized as one of the best horror games of all time, exemplified by its impressive 90 Metascore.

Dead Space 2 is a tough game on even the Normal setting, but its Hard Core mode takes it to a whole other level. Hard Core not only makes the enemies far tougher, but it also makes item drops rarer and limits players to just three saves throughout the entire campaign.

2 Outlast

Outlast - elevator

Amnesia-inspired Outlast was released in 2013 and has become recognized as one of the scariest horror games of all time, especially thanks to the player's lack of weaponry to fight back with.

Outlast isn't a particularly long game, as most players will reach the final cutscene in around 5 hours, though it's a tough experience for new players who aren't sure which direction to take. For those that have mastered the game and know the routes like the back of their hand, there is a challenge just for them. Insane difficulty removes all checkpoints and save features, meaning that players must complete the game in one run.

1 DOOM (2016)

Doomguy of Doom

Following the cancellation of DOOM 4, the path was clear for a reboot of the groundbreaking first-person shooter franchise; DOOM hit stores in May 2016 to a warm reception from fans and critics alike.

When DOOM (2016) was in development, some fans feared that iD Software would lower the difficulty level to appeal to modern audiences; thankfully, the developers did no such thing. Instead, they offered one of the hardest FPS difficulty modes ever in Ultra-Nightmare. The Ultra-Nightmare level sets the enemy's difficulty to Nightmare and forces players to start the entire game again if they die, a challenge that even the developers couldn't complete.

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