I’m pretty sure all of the UE4 MegaJam participants was really hyped in the moment the theme was announced, I was too! So, what does it really mean anyway?
Basically, it’s an old metaphor that can be traced down to the 12th century, and was recognized as most familiar expression in a letter of Isaac Newton in 1676.
If I have seen further, it is by standing on the shoulders of giants.
You can pretty much get all the info contained on wikipedia: https://en.wikipedia.org/wiki/Standing_on_the_shoulders_of_giants
And if words doesn’t interest you, this image would give you the idea!