sure but only if the person is very experienced, 2-3 hours is kinda a lot for 1 person (unless you will have a lot of fillers). But i would say for intermediate person, 1 hour re1 clone would be doable. But again you need to have a lot of experience if you are going to work on a game for 6 month especially you need to learn how to manage your project and write clean code ! My latest game " last days" i worked on it for only 3 days and my unity project was already kind of messy.