The player-character Chell is introduced to Wheatley when he revives her from her cryonic hibernation, with the intent on helping her escape the deteriorating Aperture Science facility.

While Chell and GLaDOS work their way up from deep underground, Wheatley begins fumblingly experimenting with his control of the facility, causing several key systems to fail.

Wheatley, recalling the earlier battle with GLaDOS, takes steps to prevent Chell from activating the core transfer mechanism and assaults her with bombs.

However, he did not account for tubes carrying the various gels through the room, which Chell destroys with the bombs and uses the resulting spillage to complete the attachment of the corrupted cores.

In the main story campaign, he appears in Aperture Science and occasionally aids Batman, Gandalf and Wyldstyle in escaping and surviving GLaDOS's traps.

[11] Edge staff wrote that Merchant's portrayal of Wheatley was "neurotically stuttering and blubbering" and that his "idiosyncratic staccato Bristolian burr" was a "fascinating choice".

[1] Edge staff also wrote that he served as the game's "comic relief" and called him "alternately hapless and sinister, the mesmerizing animations of his 'eye light' and a changing role throughout make him an unforgettable presence".

[12] The Telegraph's Tom Hoggins wrote that the "delightfully skittish" Wheatley's "casual, nervous patter reacting naturally to the events unfolding around you" was performed well by Merchant.

[13] He later wrote that the dialogue of Portal 2 was funny due in part to "the way that the frantic, nervous babble of Wheatley contrasts so effectively with the cynical, sinister goading from GLaDOS" and that neither are overbearing.

[17] Official Xbox Magazine's Jon Hicks praised the narrative of Portal 2 and cited Wheatley's "chirpy idiocy" as a contributing factor to its quality.

[24] Kevin Wong of Complex included Wheatley to his "best supporting character in video games", and stated that "It's hard to get angry at, or form any kind of emotional connection to, something that has no face.

"[27] PC Gamer's Dan Stapleton praised Wheatley as "fantastically voiced" by Merchant and wrote that he was "basically playing the same mind-bogglingly stupid character from the Ricky Gervais comedy Extras".

[28] PC Gamer's Craig Pearson wrote that "his nervous English voice ... is another indicator that while Valve might not have known what they had with the original Portal, this time around they’re a lot more confident".

[30] Wired's Chris Kohler wrote that "you'll fall in love with Wheatley, a friendly robot with a heart of gold and the charming voice of actor Stephen Merchant".

[31] IGN's Charles Onyett wrote that it's "difficult to overstate how Merchant's obvious enthusiasm for the role benefits the game" and that "no word Wheatley speaks is without witty inflection, and the consistently clever writing perfectly complements the onscreen action".

He also wrote that Merchant's Wheatley "steals the show" while GLaDOS and Cave Johnson's voice actors Ellen McLain and J. K. Simmons turn in solid performances.

[33] Video Gamer's Jamin Smith expressed that Merchant's voice was 'familiar' and wrote that Wheatley "possesses more personality than the cast of most other games put together" despite "a lack of any distinguishing features at all" in its appearance.

He also wrote that he was the "most delightful artificial-intelligence program one could hope to meet, and his witty quips and general clumsiness are a frequent source of amusement" and that he is "splendidly voiced" by Merchant.

[38] Editors for CNET wrote that "if Stephen Merchant doesn't win every video game voice actor award for his portrayal of the protagonist's wacky robot sidekick, there is no justice in either this world or any virtual one".