1991 was an impressive year for video game releases.
Sonic the Hedgehog, with his colourful, fast-paced, ring collecting was the top-selling title.
People were also bashing buttons until their fingers were sore, playing Street Fighter 2.
Few could have guessed at the time that one of the releases to have a lasting impact on the games industry, would be a strategy title that played like a virtual board game.
It was hardly the sexy face of a burgeoning industry - but Civilization didn't need fancy graphics, cute characters or frantic gameplay to have hundreds of thousands of people hooked.
Instead, its blend of management simulation, exploration and diplomacy, helped create a gaming icon and a new genre.
Time magazine once named it one of the 100 greatest video games. It has spawned five sequels, the most recent of which was released in 2016.
Games have changed dramatically since 1991, and grown significantly in popularity - they're now worth more than the movie and music industries combined.
Speaking to the BBC on the 30th anniversary of its release, the brains behind Civilisation is warning the games industry to remember why people play in the first place.
"The real challenge and the real opportunity is keeping our focus on gameplay," says American developer Sid Meier.
"That is what is unique, special and appealing about games as a form of entertainment. When we forget that, and decide it's monetisation or other things that are not gameplay-focused, when we start to forget about making great games and start thinking about games as a vehicle or an opportunity for something else, that's when we stray a little bit further from the path."
Dominating the market
The financial model that supports how games companies make their money has changed dramatically in the past decade or so. Now many developers and publishers rely on in-game purchases to help with their bottom line rather than solely on the up-front cost of buying a title to play.
Piers Harding-Rolls from Ampere Analysis explains: "In 2021, 79% of consumer spending on games globally was from in-app purchases, microtransactions and add-on content for games. This share is expected to grow."
Not all releases that include these mechanics have been welcomed by players - with several high-profile examples in recent years of companies having to change their approach, after a negative reaction from fans.
Some games companies are also exploring the introduction of non-fungible-tokens (NFTs) - a form of digital art that players can buy and own - into their games. There are those that believe this is an inevitable part of gaming's future and another way for companies to make money from gamers, but a fiercely negative reaction on social media has forced some to rethink their plans.
Sid Meier says that if major companies continue to focus on ways like this to monetise gaming, they risk losing the audience: "People can assume that a game is going to be fun and what it needs for success are more cinematics or monetisation or whatever - but if the core just is not there with good gameplay, then it won't work.
"In a sense gameplay is cheap... The game design part is critical and crucial but doesn't require a cast of thousands in the way some of the other aspects do. So it's perhaps easy to overlook how important the investment in game design and gameplay is."
But Sid Meier says that continued growth isn't guaranteed: "There are lots of other ways that people can spend their leisure time... I think the way the internet works, once a shift starts to happen, then everybody runs to that side of the ship.
"I think we need to be sure that our games continue to be high quality and fun to play - there are so many forms of entertainment out there now. We're in a good position... but we need to be sure we realise how critical gameplay is - and how that is the engine that really keeps players happy, engaged and having fun."
Sid says he has no plans to retire just yet, and explains the most gratifying change he's experienced during his more than 30 years in the industry, is the wider public's shift in attitude when it comes to games.
People were telling him back in 1991 that he was "wasting his time" working in games - now he smiles, as people say to him: "I wish I could get a job making games."