Co-founder and CEO of Clay.io - a hub for HTML5 games. Developer of four HTML5 games.
That happens occasionally for some reason. If you revisit the main page you may find that it did log you in. Your handle shows up in the top right hand corner of the screen. Try clicking that to re-log in....that error I think has to do with twitter oauth quotas... :-(
When I revisit it I'm still not logged in, and trying to authenticate again results in the same. I'll try to remember to check back later!
I was able to recreate the internal server error. After you log in via twitter. Just go back to the root url (http://team-us.nko3.jit.su) and the game should come up after you "sign in again". I'm still not sure twitter isn't sending that data back.
Still getting the same (though when I first visited today it had me logged in as @jasonmccloud, or some name like that). I guess this is good time to pitch something I'm a part of, Clay.io - we have an API that takes care of a few high level features for you like user accounts, leaderboards, achievements, data storage, social integration, etc. Shoot me an email if you want more info firstname.lastname@example.org