When a new entry in an established series is on the horizon, one of the more fun things to do is to go back and play the entire series. This can lead to very fun marathons, but in general, there are game sagas that are highly beneficial to play in one go.
Like marathoning a TV show or movie series, you get all the juicy story bits, and they're likely to stay in your head. Having long breaks between entries can lead to foggy memories, which is not great for stories that very much continue on from the previous one.
10 Metal Gear Solid
No other gaming series has quite the revolving story that Metal Gear does. When playing through these games, the story takes you on a ride. What's cool is that, like Star Wars, there are two orders you can play the entries in. There's release order and chronological order. Both have advantages.
Release order is the pure experience where the big plot reveals come at the correct time, but you do get a much better understanding of the full story if you play chronologically. The series' ending in MGS4 is close to a perfect ending and feels more satisfying when played through the latter. No matter the order, you'll have a great time playing these stealth action classics.
9 Silent Hill
Even though there hasn't been a new Silent Hill game in nearly a decade, its popularity within horror gaming hasn't diminished. Out of the eight main instalments, the best are the first four, and they're great for a marathon. The later games are still fun but heavily disconnected, with many plot holes. The first four are amazing horror games in their own right, and they have a continuous story.
Silent Hill 3 is a direct sequel to the first game and is much more satisfying if you just recently played SH1. SH4 isn't necessarily a sequel to SH2, but it does follow several plot points introduced there. Playing all four really allows the SH lore to flow much better, making it easier to digest and fun to boot.
8 Doom
It's wild that Doom is turning 30 years old in 2023. The original game still plays great and has a seemingly endless amount of mods and community-created maps. There are six official classic Doom campaigns, not including Doom 64, and they're still a blast to play through. Plutonia Experiment, in particular, is amazing with its challenge and pure carnage.
Even the more modern games are worth playing. Doom 3 feels a little like Dead Space, and while it has a slow start, it really picks up in the last third. Then Doom 2016 and Doom Eternal are some of the best FPS games in recent memory. It's a blast of a marathon, particularly the classic games, due to how surprisingly well they hold up.
7 Dead Space
The premier sci-fi horror gaming series has to be Dead Space. System Shock is a close second, but Dead Space has so many elements going for it. Its nightmarish enemies and environments, interesting story, but the main driving force is its monster encounters.
Enemies come from anywhere, and this makes the game consistently tense. It's one of those games you have your weapon drawn a significant amount of the time. Playing all three instalments is a blast, and it helps there are only three games plus one remake. If there were more entries, then the horror experience might get old, but that isn't the case.
6 King's Quest
Any classic point-and-click adventure series is great to marathon, whether it's Monkey Island, Sam & Max, or Leisure Suit Larry, but the most underappreciated one is King's Quest. Often criticized for its brutal difficulty, the series was genius in its own right. Taking common fairy tales and giving them a comedic spin, you truly felt you were on a massive adventure.
The classic series primarily follows the royal family of Daventry, with the two main leads being King Graham and Prince Alexander. With a continuous story, it definitely flows better to play one after another. Plus, some villains return in later games, and their inclusion is much more impactful if you already know them.
5 The Witcher
One of the best RPG series of all time is The Witcher. The story follows an all-time great protagonist in Geralt of Rivia as he tries to regain his lost memories and save the world from the Wild Hunt. While a lot of folks probably started with either Witcher 2 or 3, the series is best experienced in order.
Many of the plot points as well as Triss's romance, if you go that route, are most satisfying if you play all three. The first Witcher has aged a bit, which is why a remake is on the way, but that probably isn't coming for a while. It's a PC and Mac exclusive, but console users should start with the first game because you'll miss so much if you start with any of the sequels.
4 Batman Arkham
While Spider-Man has great new Superheroes games recently, the big dog before him in the genre was Batman. All four entries in the Batman Arkham series are quality, including Arkham Origins. For some reason, that game tends to be left out, even though it does many things better than the true sequel Arkham Knight.
It's a really fun marathon, especially if you love the universe, as there's a massive amount of Batman characters with solid voice acting to boot. Arkham Knight delivers a weird but satisfying finale that hits harder if you're playing in order. An extra thing to note is that playing the DLC isn't necessarily in the bigger picture, so they can be skipped.
3 Ace Attorney
It's funny to think that when the first Ace Attorney was launched in the West, nobody thought of it as a visual novel, even though it is. Gameplay in Ace Attorney is diverse for its genre but still focuses on the characters and plot. Both are phenomenal, with likable characters, nasty villains, and a constantly evolving story, even though it can get ridiculous.
With all this focus on story, it's best to play one after another as later games do build on the narrative from previous instalments. Some running gags also return. The Ace Attorney games are especially important to marathon because they, unfortunately, lack replay value. You'll probably play and enjoy them once and then move on. This makes it harder if there's a long gap between playing entries.
2 God Of War
The most acclaimed God of War games are the newest two, but you have to play all the ones before to get the full grasp of Kratos' story. You will not be disappointed as the six classic God of War games are still fun today, mainly because they feel very different from a lot of hack-and-slash games now.
Most feel like Devil May Cry or Bayonetta today, but God of War was an American hack-and-slash contrast to most others at the time, which were by Japanese devs. This gave it its own flair and feel, refreshing in current times. None of the classics are lengthy either, which makes it great to marathon.
1 Mass Effect
Some people consider the original Star Wars trilogy one movie since they tell a very cohesive story within them. The video game equivalent would be the Mass Effect trilogy because it is essentially one big game. Mass Effect 1 through 3 very much feels like one complete story, and you can even plot out its three-act structure.
Your choices here have major ramifications not only in the present game but in the sequels. This makes continuing right into the next entry much more enticing. Plus, the bond you create with all your beloved companions is fully fleshed out throughout the games and DLC content. There is absolutely no reason not to play all three games in succession, especially since most today are playing through the Legendary Edition.