In the digital era, some people must use technology to support their works or even their pleasure time. A game is one of the digital applications for some people to spend their leisure time, including children. However, indirectly, a game also can be an educational tool for children, especially for language. Based on the description, the discussion of indirect language acquisition especially occurred outside of the classroom is rare to discuss. This paper investigates the effect of a video game on a young gamer toward English Vocabulary Improvement. As it is a case study, the boy in the study is a ten years old young gamer, named Khalifatul Fajriatil Fattah. Commonly, some young students cannot speak English or even do not have some English vocabularies in their mind. Data taken included vocabulary size and word recognition tests followed by writing vocabularies and translating the meaning test. In addition to this data, qualitative data in the form of interviews were included to support the findings of the vocabulary tests. The data will be taken on how the young gamer can conclude the meaning based on the context and not based on the dictionary. It has resulted that incidental encounters with the same word and phrase may have played a part in the above-mentioned benefits. Then, the child also can know the meaning based on the performance of the game itself. Motivation to play the game was also upheld according to the qualitative data.