The use by Rembrandt of the Caravaggio-esque chiaroscuro is the most apparent in this painting, with Ganymede drenched in light to signify his significance in this scene. You will have seen a similar technique in his Danae, another mythologically themed artwork.
This frightening, brutal scene makes use of Rembrandt's skill in achieving an extraordinary realism in his work, a development from the earlier Renaissance artists. This painting was also produced on a huge canvas, allowing the artist to add endless detail to the key figures of this composition. As his career progressed, viewers would need to stand further back as his work were no-longer intended to be seen up close.
This abduction has been captured by many artists within the Renaissance, all offering a slightly different perspective on the story of how Jupiter would transform himself into an eagle in order to carry the young man off to Olympus, where he would be used as a servent. The variations with Rembrandt's work may depict a later moment when the eagle has actually taken flight off back home with its prized asset in its clutches.
Rembrandt completed a study drawing for this artwork though the figures at the bottom of it would not make it into this final oil on canvas. It was clearly a quick sketch just for the purposes of fleshing out a rough layout for the composition, with very little detail added.