Here in Ether 10:21, Oliver Cowdery initially wrote “to get gain”, perhaps because he expected that phrase. His correction to game appears to be virtually immediate (there is no difference in the level of ink flow for the supralinear game). There are 19 instances of “to get gain” in the text (as well as three of “to get power and gain”), but there are no more of “to get game”. (The text has three more instances of the noun game in reference to wildlife, but none occur in the expression “to get game”.) Here in Ether 10:21, 𝓞 undoubtedly read “to get game”. Interestingly, one of the actual instances of “to get gain” is found in the very next verse: “that they might get gain” (Ether 10:22). That particular instance is found exactly two lines below in 𝓟 (and undoubtedly it was similarly positioned in 𝓞 as well, although 𝓞 is no longer extant for this part of the text). Perhaps Oliver’s eye caught a glimpse of the following get gain as he was copying the text from 𝓞 into 𝓟, thus prompting him to initially write “to get gain” here in verse 21.
Summary: Maintain in Ether 10:21 the unique occurrence of the phrase “to get game”, the corrected reading in 𝓟.