Complex sentence: Video Walkthroughs (video games) are tutorials in which a player records and uploads themselves playing video games to a video sharing site like YouTube with the goal of assisting others in accomplishing feats within the video games.
Split into simpler sentences: Video Walkthroughs (sometimes referred to as a'playthrough') are videos in which a player records and uploads footage of themselves playing video games to a video sharing sites like YouTube. These videos generally have the goal of assisting others in accomplishing feats within the video games.