Sorry if you saw my earlier reply. No, it turns out members cannot invite more than five people to a private chat / direct message. Here is the official notice on this: "It's a user group / user permission setting - Maximum conversation recipients." Unfortunately, I have not been granted permission to modify this setting.
I'm assuming, furthermore, that (to further clarify your question) that this limit is in total. In theory then, you should be able to invite some now and some later to a total of five. Let us know how you make out.
I don't think it has anything to do with the quality of the game, just how much time and interest other members have in reading/participating in the forums. I am glad, however, that they are focusing their limited time on more important topics. And can you blame them for not wishing to play a forum game when there are so many awesome Mekorama games?
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