Two of the most interesting games released over the past few weeks were also two of the strangest. One was a dubstep-infused trip down memory lane, while the other starred a 90s basketball star and a talking bear in a sweater. Both were created by notable developers, and both are quite fun to play, with simple mechanics and retro sensibilities. They also have one other important feature in common: they're ads.

Old Spice's Dikembe Mutombo's 4 1/2 Weeks to Save the World is a curious beast. It's a joint effort between advertising firm Wieden + Kennedy, Powerhouse Animations, interactive studio Driftlab, and a team of indie developers lead by Canabalt creator Adam Saltsman. The entire project is essentially a bizarre game jam, where new chapters are added to the game each week, and are built under a tight deadline. It all starts with Wieden + Kennedy giving Saltsman an outline of what the game should include — which, as he explained to Polygon, can feature such bizarre phrases as "descending down the throat of America" and "a boss fight with the state of Ohio." The team then spends the next five days turning these ideas into a game. "The main challenge is creating something really cool in less than a week, each week," says Saltsman.

Combining advertising and games isn't a new concept. There have been games based on corporate mascots and ones about the great cola wars, and at one point even Burger King was selling physical copies of its own Xbox 360 games alongside Whoppers. But the web and mobile platforms have opened up the idea to a wider audience. It's not only easier to make these games, it's easier to get them in front of people. And advertisers are taking advantage.

The other thing that's changing is the quality. Instead of a terrible freebie featuring a new car or soft drink, many recent advergames are quality titles in their own right, built by indie developers of some acclaim. Prior to working on 4 1/2 Weeks Saltsman had some experience working on corporate tie-in games, having helped make The Hunger Games: Girl on Fire for iPhone, which was used to promote the film. He says that, from a small developer's perspective, these kinds of projects offer both pros and cons, providing "great access to all sorts of crazy resources, but tight schedules, and occasionally complex approval hoops."

Gamers typically aren't too receptive when it comes to mixing their favorite hobby with advertising, but Saltsman believes that games that are upfront about being an ad have an advantage over those that aren't.

"I think games that are really blatantly advertisements affect people differently — to me they are much more honest," he says. "Like if you have a game and you say to someone ‘hey check out this fun game, it's just a plain old fun game, no agenda here' but then it secretly totally has a commercial agenda, I think that really rubs certain people the wrong way, myself included. But if the game says, instead, ‘hey there! I am an ad for a commercial product. Great — now that we've got that out of the way, let's have some fun!' that is really honest and direct I think, and I think people respond in kind."

But while Saltsman only occasionally works on these kinds of projects, others have made an entire career out making so-called advergames. Like Jason Oda, for instance. After gaining some notoriety creating the viral Flash hit Emogame, Oda started taking on game projects to promote bands, and eventually ad agencies began tapping him to create titles for their larger clients. His latest release, Skrillex Quest, is a 3D action RPG that takes place inside a world of NES game cartridge glitches, and it's the project he says he's most proud of. It was commissioned by Atlantic Records, and previously Oda's work has been used to promote everything from Meow Mix and Jiffy Lube to The Chemical Brothers and Fall Out Boy. Depending on the project, his creative freedom can vary quite a bit.

"For bands I have lots of control and it usually ends up being great because of that," he says. "For ad agency work, I rarely get to come up with the concept and it's really hard to get both art directors and clients to do anything that's actually going to go viral. Generally people want to be as safe and basic as possible, so that's generally what happens. Bad art directors don't want to push the client and in the end you get something that's cool and well done, but not necessarily going to be passed around. You run into a lot of friction with people who don't even play videogames that all of a sudden have a whole lot of input such as ‘do we really need bad guys?'"

To Oda, this virality is what makes an advergame a true success, though he also admits that it's pretty rare and dependant on a number of factors. "It usually requires something that is pop-culture relevant and something that is only subtly pushing whatever it's selling," he says. Depending on the brand, games aren't always the best advertising option either. While they work particularly well for bands because people are able to listen to music while they play, other types of brands won't necessarily be able to showcase their product quite as well, though they can get around this by being a bit more flexible — something the Old Spice game is a prime example of. "Some brands that are open to being weird and doing innovative pop culture-relevant things can benefit from a game," Oda explains.

Though advergames have been around for some time, it seems that the recent meme-worthy incarnation could end up becoming a growing trend — or it could simply be a short-lived fad. Despite his chosen career path, Oda actually believes that we'll see far fewer advergames in the future, though this will have the side benefit of weeding out the low quality releases. "I think people who do good work and have a good team behind them will still make quality projects," he says, "and the people in charge will figure out it's probably not worth it to make a half-assed game."

Even if the quantity decreases, though, it's likely that we'll continue to see plenty of smaller developers partner with advertisers on creative new projects. It helps the developers reach a wider audience (not to mention make a few extra dollars), and the advertisers are able to produce a unique experience that has the potential to spread around the web like crazy. "It's really win-win for everybody involved I think," says Saltsman.