Get ready for a new experiment in online gaming: A game universe that’s tied directly into a television show.

Trion Worlds on Wednesday showed off a preview of Defiance, a persistent open-world shooting game that takes place in the same universe as an upcoming science fiction television show, also called Defiance, that will air on the SyFy channel. The company announced the game at the Electronic Entertainment Expo in Los Angeles, Calif.

The tie-in means that any event that’s significant in the world, such as a cataclysmic event or a change in the balance of power, will take place in both the game and the series. But the worlds are loosely tied: The game takes place in San Francisco and the series takes place in St. Louis. As a result, the game and series directors can efficiently coordinate events between the two parts of the experience without having to worry about the logistical nightmare of having them tied together all the time. The game and series will be closely tied together, but separate enough to be avoid major consistency headaches.

That also means that the show’s directors can decide to send a character from the series over to San Francisco, and that character will appear in Defiance’s in-game world. Players can interact with that character before he or she heads back to St. Louis to rejoin the cast of the show.

Characters on the show will also talk about some of the most powerful and well-known players in the Defiance world too, said Robert Hill, senior producer at Trion Worlds.

“A character might be like, ‘I just had the most amazing experience in San Francisco,’ and you can be like ‘I was there!’,” Hill said.

Defiance is a third-person over-the-shoulder shooting game like Gears of War. It’s set in the not-too-distant future when Earth has been attacked and partially terraformed by aliens. The open world is part of the San Francisco Bay Area, so it will feature landmarks and other indicators that show the world is still Earth — though it’s lush with alien vegetation and life forms.

Like other MMO games, there’s a progression system that lets characters get experience points for completing objectives and killing enemies. They eventually level up and unlock new skills and abilities and get more health and armor when they earn enough experience points. Some of the skills in the game include creating holograms to distract enemies, lassoing enemies with an energy rope and pulling them nearby or cloaking in a stealth field and sneaking by enemies.

The combat looks very fast paced and it isn’t like some cover-based over-the-shoulder shooters that can sometimes leave players stranded behind walls while they wait for the right time to strike. Players can dash, shoot, jump and jump a second time while in the air in order to avoid attacks from enemies. It seems like the game revolves more around “twitch” gameplay, which relies on players’ skills and reflexes rather than progression in the game to make them more powerful.

The game looks great for an MMO — but that’s to be expected from Trion Worlds, which also runs Rift, another MMO. Rift also looks gorgeous and the worlds are very dynamic and feature a lot of moving objects and environmental effects. The Trion Worlds employees demoing the game blitzed through three or four quests throughout a ten minute demo, so it seems like the progression is very quick and players will be able to cover a lot of events in a short amount of time.

It looks like the game is not relying on “instances,” which other MMO games typically use on to segment the world and make it a little more bearable for the servers on the back-end. For instance, in World of Warcraft, the system transfers players over to separate servers when they are running through a dungeon with five or more people. This use of separate instances helps the back-end servers because they aren’t constantly bombarded with information from everyone all at once. It also means the players get access exclusively to bosses in an instance rather than having to camp out and wait for a boss to re-spawn.

In contrast, Defiance looks like it has players rushing around the world and jumping in and out of groups on the fly to complete quests. When players run by another group completing a quest, they can quickly drop into that group and help complete the quest and then continue on their way. They can also turn and take potshots at the other players if they’re feeling particularly malicious.

The same is true for the games’ large-scale events, called Arkfalls. Those feature large alien-like structures crashing into the group in the open world. All players in the area take place in the Arkfall and have to fend off aliens throughout the event. The Arkfall in the demonstration had players gunning down a giant terraforming pod to spawn a boss. The players then have to take down the boss to get access to the game’s most powerful rewards, and they are split evenly among all players that took place in the Arkfall. It looks like there is theoretically no limit to the number of players that can participate, compared to the limits in other games like World of Warcraft, which cap raids at 25 players.

All that being said, the combat demonstrated at E3 today seemed a little clunky. The movement of the target reticule wasn’t smooth and the hit detection on enemies looked a bit dodgy. When they shot at an alien’s head, the graphic would show up on the alien’s legs and torso even when it was the first shot fired at close range. A lot of that probably has to do with the early nature of the game. The shooting seems a little less refined when compared to other shooters like Gears of War and Uncharted. It also seemed like the skills they were using on-screen weren’t really helping much and the players were just blasting through the game with guns blazing and there wasn’t much strategy involved.

A few companies have taken a crack at creating an open-world MMO that features twitch-based gameplay and shooting. Sony was an early candidate with Planetside, a first-person shooter open world that launched in 2003, to moderately good reviews but was knocked off rails by a weak expansion pack that frustrated gamers. While the Trion team demoing the game was showing it on both an Xbox 360 and a PlayStation 3 simultaneously, the games will all have discrete worlds. That means that PC gamers will only play with other PC gamers, Xbox 360 gamers will play with Xbox 360 gamers, and so on and so forth.

“Those decisions are only up to the platform holder,” Hill said. “Right now we can do cross-platform play but we don’t expect to have that at launch.”

The game will launch relatively close to the television show, but Hill wouldn’t give any additional details about when it will launch. It will go into a closed beta before it finally launches.