We recommend playing the games with a partner because sometimes it can become logistically challenging to play, watch, and record the answers for each game. The other reason we recommend it is because we have found that not all dogs obey the sit and stay command.
That said, if your dog doesn't have a problem with the sit/stay command, and if you are comfortable with playing alone, go for it! Another solution to playing the games is written in a blog post, which you can find here.
Keywords: partner, single, alone