is it possible to make an mmo OGame or Travian like with C2?
if yes, is there anyway kind of guide?
Yes, but, first make sure you are very familiar with Construct 2. There are turorials for working with multiplayer in the tutorial section.
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yes, very possible. However I do not recommend using C2 as the backend server, but just as the client/browser side of the game. SQL+scripts (perl/php/ruby take your pick) will work much better.