Gamers who like playing strategy games often have a far higher tolerance for lengthy gameplay than most. Some strategy games, like just about Civilization game, can take weeks to get through, and there's always the allure of "just one more turn".
However, some strategy games take a lot longer than others to get started, considering the length of tutorials and the game's learning curve. Oftentimes, players don't truly get good at the game until several hundred hours in, thanks to a huge skill ceiling or complexity of the simulation.
10 Cities: Skylines
The city management game Cities: Skylines takes a lot of inspiration from old isometric city-building games like SimCity, but stands apart thanks to its dedicated modding community and the complexity of the game's systems.
Learning the strategies necessary to maintain a city long-term, though, can take a player hundreds of hours. When first starting out, most players will follow in-game tutorials as well as online fan-made guides for a long time before even being able to maintain a small village, let alone a bustling cityscape.
9 Stellaris
Where Cities: Skylines is about managing a settlement on Earth, Stellaris is about managing an empire in space. It's an extremely complex, deep game with incredibly gorgeous vistas throughout space.
While the in-game tutorials do a decent job of getting a player ready for a playthrough, it will take dozens of hours to truly get a hold of the vast number of interactions and consequences throughout the game.
8 Civilization Series
The Civilization series, most recently with Civilization VI, is known for the incredible length of its games. Choosing to play on certain settings, like the infamous Marathon mode, will lengthen the game dramatically – and things don't truly get spicy until the player encounters other civilizations.
While Civilization is pretty easy to understand for beginners, the game has a huge skill ceiling. The best players treat the game almost like Chess, and consider every future move from the founding of their first city.
7 Planet Coaster...
Planet Coaster is more roller coaster theme park simulator than it is strategic. However, choosing to play on any difficulty aside from Sandbox will make the player responsible for effectively managing a sprawling park, which is a lot harder than it sounds.
Whereas games like Roller Coaster Tycoon 3 are extremely easy to understand, Planet Coaster has countless systems throughout the game that must be monitored for maximum success. It takes a while to build a park, though, and even longer to fully understand the depth of the game's mechanics.
6 ...And Planet Zoo
Planet Zoo is the spiritual successor to Planet Coaster except instead of a theme park, the player must manage a zoo. Whereas Planet Coaster is more of a simulator game, though, Planet Zoo is a strategy game at its heart.
There are so many things to consider and it can take hours of micromanaging effort to get just one exhibit ready for audiences. Planet Zoo features a number of mechanical improvements over Planet Coaster's engine, too, and players will spend days in-game before having anything to show for it.
5 Total War Series
The Total War series of games is one of the most well-recognized grand war strategy series out there. Entries span the breadth of history, as well as the Warhammer universe, and it takes almost as long to fully learn how the Total War games are played properly.
Each game has an in-game tutorial, and the games themselves are not particularly lengthy. However, the games are far more complex than first meets the eye, and players won't truly feel comfortable for a good portion of their first playthrough.
4 Starcraft II
Starcraft II is a game that embodies the phrase, "easy to learn, hard to master." The game is a classic RTS game, where turns are simultaneously taken to acquire the same resources and defeat the opponent. While the campaign AI leaves much to be desired, online games are where Starcraft II skill is really shown.
The campaign for Starcraft II, though, is much longer than it needs to be. Each level in the campaign can take an hour or more to complete, and the meat of the game is found deep into the campaign and DLC.
3 Europa Universalis IV
Europa Universalis is a grand strategy game that takes place from the Rennaisance to the late 1800s as the player commands a historical empire. While it has been compared to Civilization, it's much, much more complicated.
The game requires the player to have on-hand knowledge of the near-countless resources, relationships, and interactions the empire has with others constantly. It takes a certain kind of patience to play a game as complex as this.
2 XCOM 2
The strategy of XCOM 2 is somewhat based on combat strategy in tabletop board games. It's turn-based and gives players a set number of actions, including character-specific moves, "classes," and takes into account environment into its combat calculations.
The campaign takes a long time to build, though, forcing players to go through a lengthy few forced quests before being given any options. Even then, the quests for the first few hours of the game must be finished before unlocking most of the game's actual content.
1 Mount and Blade: Bannerlord
Mount and Blade: Bannerlord is somewhere between an RPG and a strategy game. The player interacts with NPCs, factions, and goes toe-to-toe in physics-based combat, but there is also the end-game empire management portion that is almost entirely strategy.
While the first two-thirds of any Bannerlord playthrough will be almost entirely RPG-focused, that last third is about managing diplomacy, the economy, feeding your empire's armies, and of course, defending against attackers.