No, at the moment there is no way for players to change their game names. Prior to our first rejection the whole account/character system was different. In changing everything to try and get approved, renaming an existing character just got overlooked. I'm sure we'll get to it at some point.
If you really want a name change, file a bug report and tell me what you want. I don't believe it will change in any existing games, only in new ones.