Beach and Labrat levels where switched? I even wonder where you got OEM...
However, there are lots of events that aren't finished, for example the bee's event does not work correct (tough it's still a very useful enemy), Springcord doesn't appear and many other events also do not work. Tweedle seems to be one of them. Maybe Epic ran outta time and so they just did not finish them because they wanted to release JJ2. That's done often in gaming, for example look at Tomb Raider (not Rabbit ): The Angel Of Darkness. It's totally unfinished. We may never know..