From the moment the second game in Valve's acclaimed physics-bending series debuted in 2011, fans have been asking for Portal 3. Portal and Portal 2 are unequivocal masterpieces that took a simple concept and utilized it to maximum effect. With a sequel that doubled down on the first game's mind-bending puzzles, signature sense of humor, and well-realized cast of dysfunctional characters, an appetite for further physics-based fun remains undiminished. Series co-writer Erik Wolpaw expressing his desire to make a third game has only heightened the clamor to a fever pitch.

However, fan desire doesn't always translate to fan fulfillment. Valve president Gabe Newell has previously expressed his desire for Valve to work on more multiplayer-focused games, while Wolpaw has indicated that certain other Valve properties, such as Counterstrike, are far more profitable. Regardless of whether it's likely or not, fan interest in a third Portal game has been revitalized -- but there are some things a hypothetical Portal 3 would need to do to satisfy fans.

Portal 3 Needs a Fresh & Engaging Story

If Portal 3 were to become a reality, Valve would need to make practical considerations of how to evolve the series. Portal 2 wrapped things up, with Chell escaping her incarceration in the Aperture facility, Wheatley orbiting in space, and GlaDOS achieving some form of closure, which doesn't leave much in terms of sequel plot hooks.

A prequel set in the labs when they were still fully operational is one possibility, either delving into the backstory of owner Cave Johnson and his assistant Caroline (who would become GLaDOS herself), or else the tribulations of former Aperture Science employee Doug Rattman before the facility was flooded with deadly neurotoxins. A God of War or Mortal Kombat-style soft reboot is another viable option, though rebooting a series after just two games seems unlikely.

Evolve Portal's Gameplay Without Removing Its Soul

Chell Observes The Puzzle Room In Portal

Portal 3 must move its gameplay forward to be considered innovative while keeping much of the heart and soul of what made the first two games so exceptional. Even Portal 2 received a small degree of criticism that its looser, more expanded narrative had the potential to detract from the taut, lean feel of the series' puzzle-based gameplay. A third title runs the risk of exacerbating the issue by pursuing a grander, more expansive feel.

A third game could return to Aperture Science Inc., or else make use of a grander scope and scale by freeing the game from such shackles, either making it more explorative or at the very least introducing a range of locations and backdrops other than the visually repetitive aesthetics of Aperture's laboratories. How this would be incorporated into a new narrative, however, remains a tricky proposition for the new game's would-be writers.

Don't Lose Portal's Signature Sense of Humor

Chell carrying Wheatley in Portal 2 game

With the right team and a solid balance of innovation and reverence, it's certainly possible to recapture the magic of the first two games. The key to this will be understanding the particular comic style that has made the franchise so acclaimed. Iconic quotes from GLaDOS, such as guilting the player by saying one of her central cores "made shoes for orphans" upon its destruction, won't be easy to match. Making games genuinely funny is an tricky feat that few truly manage to pull off, but Portal 3 must find a way of recapturing the dark humor that has become a staple of the series while finding its own unique voice.

Portal 3 Has to Find the Right Difficulty Level

PS3 Portal

Both Portal games were known for being challenging, but this was a facet that enhanced their reputations rather than being seen as an unnecessary impediment. Both demonstrate a mature approach to the concept of the difficulty curve, each one gradually ramping up the challenge without simply becoming unplayable or needlessly opaque. It is this trick that a third installment would need to pull off once more, providing sufficent guidance while still giving players the unique satisfaction of figuring out the game's most mind-bending levels.

Portal 3 Needs to Live Up to High Fan Expectations

Portal 2 co op robos - peabody and atlas

Whatever Valve releases, fans will be expecting something exceptional. Portal devotees have been clamoring for a new chapter in the Portal saga for over a decade, meaning there's a lot of pressure on Valve to get this hypotheical game right. With the standard set so astronomically high, the weight of expectation is crushing, and were a third game to materialize, the developers would need to ensure they put out something truly spectacular to avoid sullying the franchise's reputation.

The odds might not be stacked in Portal 3's favor, even with the significant desire for a return to Aperture's Enrichment Center, and there is always the fear resurrecting the franchise would only serve to damage the legacy of the two games already in existence. The flip side, of course, is that were Valve to make the decision to green light a conclusion to the trilogy, it's probably one of the few studios that is capable of pulling it off and giving fans the game they've been craving for over a decade.