The phrase "game installment" refers to a new version or part of a video or computer game that is released separately from previous versions. Full definition
Dark Souls 2 continues on very much like the previous video game installments. (fraghero.com)
New characters, deeper mechanics and fresh takes on existing modes are just a few of the properties present in improved fighting game installments. (heavy.com)
So far, what we know about the video game is that the title will take place in a parallel world of events from the past video game installments. (gameranx.com)