I noticed this when coming across this jam, and had a similar point of criticism, also this language is a bit vague.
"All Entries become the property of the Sponsor." - which implies that we could possibly not have ownership over the IP at the conclusion of the jam.
"non-exclusive, transferable license" - non-exclusive implies that access isn't restricted to the sponsor.
So would we still have access to developing our concepts further post jam if we don't win any of the offered prizes, and the jam version of our games would be accessible and usable by CoolMathGames for free? Or is the intent that ownership completely transfers to CoolMathGames regardless of the outcome of rankings?