The one genre Hollywood can't seem to crack is the video game adaptation.

For every "Mortal Kombat" there's, well, a landfill of truly unwatchable misfires. "Assassin's Creed" is the latest adaptation to get the big-screen treatment, and it hopes to succeed where too many have failed.

Michael Fassbender both produces and stars in the adaptation of the hit Ubisoft game, playing Callum Lynch, a troubled convict who, soon after seemingly being executed, wakes up to find himself a member of the Assassins -- a secret order of time-traveling killers (naturally) who revisit the past without the aid of a Flux Capacitor. With the even-more secret and dangerous Templars as his target, Callum must parkour and kick-punch and stab his way through history. (To say more about the plot would spoil the fun of finding it out for yourself, especially if you're unfamiliar with the incredibly popular -- and excellent -- game.)

"Assassin's Creed" reunites Fassbender with his "MacBeth" director Justin Kurzel (above), the latter of which recently screened both the first trailer -- which drops today -- and the first reel of the film for journalists in London. It's a ballsy move to show the first 20 minutes of a film that's very work-in-progress, but the director was nothing but confident about the presentation -- which serves as an origin story for Callum, who starts out as a young boy in New Mexico and grows up to become Fassbender after stumbling upon the aftermath of his mother's murder at the hands of his hooded, stab-happy father.

The film opens with an eagle soaring through and around arid peaks, gliding over a bare-bones town in the desert before finding young Callum -- wearing a hoodie -- and embarking on a very long ride home on his BMX bike. The bike ride is very anti-climatic; given the significant time spent on Callum's back as he rides through town, one expects the action to reveal something important about the character's skillset or personality that not only establishes him as an ideal future member of this cabal of assassins, but also as someone the audience can truly invest in. (Outside of briefly popping a wheelie, we don't get to know much about this kid other than he's soon to become an orphan.)

He finds his dead mother at the kitchen table, suffering from a very bloody neck wound. The cause? Callum's father, who stands near the body sporting the game's signature knife gauntlet weapon -- one his son will soon wield. From here, we jump forward in time to the moments before adult Callum's execution, which he spends adding new charcoal drawings to his cell's collection (pictured below).

A priest enters to give him last rights after discussing a key Robert Frost poem that has thematic ties to the film's more cerebral undertones, all before Callum is administered lethal injection in one of the reel's more chilling (and dramatically realistic) scenes. Callum awakens to find Sophia Rikkin (Marion Cotillard) speaking cryptically about why Callum was spared and what she wants with him. Unable to use his legs properly, Callum stumbles off a gurney and into a secret facility -- all concrete and cold steel -- to discover that his the bloodlines of his past is key to whatever future he has left.

Fans of the game will be glad to know that the epic "leap of faith" has made it to the screen -- we glimpsed the game's signature move in action. The fight scenes are shaky-cam violent and not afraid to push what looks like PG-13 action to the edge. (Though it is a bit weird that, with such a high body count as a result of stabbing, not one bad guy bled in the footage screened. That could be because the filmmakers are going the route of CG blood to be added in post.)

A POV shot from the perspective of Fassbender manning a bow and arrow really blew the crowd away, as the first-person viewpoint is a popular one in video games.

And Fassbender strikes a powerful figure while wearing the game series' iconic attire. He looks to be having genuine fun in the role. While it is too early to tell how this all adds up in the final product, it's clear from jump street that Fassbender is very invested in the material -- which his director reiterated during a post-screening Q & A, adding that the actor-producer was surgical with his notes as the filmmakers shaped the story.

Here are more insights we learned about the "Assassin's Creed:"

1. The film features all new characters, "designed and created from an original story," revealed the director. But he insisted that "the concepts of the game and the spirit of the game is there ... the idea of having access to your memories, the idea of history and who you are. It's an origin story, so it's about a man who discovers who he is, and the fact that these lives lead back through the years and year and generations and generations."

2. For Kurzel, the game's themes are what drew him to the film. "I think it's the idea that you are defined by your history. Our characters have no idea who they are -- actually, they belong to a tribe that is 5,000 years old. So that concept is very cinematic."

3. When it came to adapting the game, the director did not feel any constraints imposed upon him by Ubisoft. "I didn't feel like we were adapting a video game," Kurzel said. "It wasn't as if we were looking at the [game's] Bible and saying, 'We have to have this and this and this.' But I think it's the ideas in the game that make it so popular. It's so human and rich and universal and we're really just extending on that."

4. Fassbender got involved with the film very early on in the process, and brought his "MacBeth" director with him. Kurzel was approached for "Assassin's Creed" while he was still editing "MacBeth."

5. The filmmakers were committed to grounding the action by keeping the stunts as practical as possible.

"We didn't want our assassins to float through the air. We want them to land with a thump. [Fassbender] was very keen on doing a lot of stuntwork himself and for it to feel real. I just didn't want to be in a parking lot with a huge green screen."

6. Discussions are currently underway in regards to how much of the film will be presented in IMAX.

7. If you like first-person shots, then you can expect the film to deliver on more of that. "We put a lot of GoPros on blades and on the arrows and it wasn't to imitate the point of view of the game. It was actually to make you feel the point of view of Cal."

8. A key piece of tech from the game, the Animus, gets a big-budget upgrade. Here, it serves like a swing-arm attached to the assassin, moving him around a virtual-reality environment as the person using it travels to that physical environment in the past. The film will blend scenes in the Animus room with those from the past, adding an interesting dynamic to the action as Cal battles in both the present and during the Spanish Inquisition.

9. And yes, the filmmakers have discussed -- "over a couple glasses of wine" -- about a sequel. "Where do we go next," Kurzel said. "It's a delicious cocktail of possibilities. The idea that Michael can go in any kind of time period and play different ancestors is very exciting. You could go for a second or third film, but we're just trying to finish this one."

"Assassin's Creed" hits theaters Dec. 21.