Took me 1 sec to google and find
[quote:26ceng3r]Try it in the Free edition
You can even try out the Multiplayer feature without a license! Download the Free edition and get started. However note you cannot export projects using the Multiplayer feature with the free edition. Purchasing a license and then you can share your multiplayer games with the world!
And it is as clear as day here in the limitations of free edition.
If you use any free(limited) program, you always check what the limitations are - that is the goto place for every piece of software - it helps you decide if you want to purchase it, if you need to purchase it etc.
Because you failed to do what, everyone one else does isn't scirra fault, and lets be honest here, if you are annoyed, best be annoyed at yourself.
BUT, I understand your frustration, but you have to understand that scirra can't give away all the best features for free, they are already being more than generous with the current free edition.
And when using a limited free edition, it is your responsibility to actually check the limitations (which have been publicized extremely well - took me 1 sec to get the facts). And its common knowledge that free edition (DEMO VERSION) will have limitations. Scirra also right from the first mention of multiplayer said that it was strictly going to be for paid versions, that is all their press releases etc.
If you are a student, then why not investigate get your school involved - very affordable for schools.