In short, you work for them, for free. You don't win unless you check all of the beaurocratic checkboxes. If you make something good, you might win $20k, $10k, or $5k, but good luck with any further monitization, as you give them right to use it forever (not for "commercial" use, but the "educational" catch-all is pretty broad). It's non-exclusive rights, of course, but why would I pay you for it when I can get it from the LOC for free?
The game is required to be in the browser. It's pretty obvious that they plan to put this on their website, or perhaps even create a portal for these types of games to point teachers to.
I also found it interesting that they require a cheat code to allow judges to play all levels.
And, they don't like copyleft licenses, either. LOL.
"If you win, in consideration of and by accepting the prize, you hereby grant to the Library the worldwide, nonexclusive, transferable, perpetual, irrevocable, fully paid-up/royalty-free right to use the entry that I (or my team, as applicable) has submitted to the Challenge, consisting of the game itself and the description thereof (“Entry”), for noncommercial purposes in connection with the Challenge and otherwise in furtherance of the mission of the Library of Congress, including, without limitation, associated promotional and educational purposes. This right includes the right to reproduce, prepare derivative works from, distribute, perform, display, or otherwise make use of the Entry, in any form, media, or technology, now known or later developed, including television, radio, satellite, cable, and the Internet (including, without limitation, streaming, podcasting, and on websites with user-generated content, such as Facebook and YouTube). You must also allow us to use your name, brief biography, and likeness, or if you are a minor, your first name, last initial, and state, to promote the challenge."
"The game must be accessible to disabled individuals. Many people with different abilities use content and apps from the Library of Congress. We have to make sure everyone, including people with disabilities, can use anything we post."
"Where there is a choice, use the most permissive license (i.e., the one allowing the broadest unconditioned use; please avoid viral licenses such as GPL)."
"i. Be Section 508 compliant.[1] ii. Work with screen readers like Jaws, NVDA, VoiceOver, etc."