Most people are, since they were expecting something and didn't get that... you know, the usual Hype Kill Effect. If you tell that hype to shut up and just play the game with the intent of being an insane mad scientist, it honestly is no different from being a child and being handed Legos to build insane vehicles. Hell, the trailer in the demo after clearing it showed that they built a Gundam (pretty big in size) and were fighting a boss with it. Some reviewers were saying that you can approach challenges differently because of this. IGN's cited a sumo wrestling match where you build a heavy car to push the other heavy car off the ring. But instead of doing that, the guy built a light vehicle, but made part of it spring ejecting and ejected from the car at the last moment, cause the big guy's momentum to work against him and he went flying off the arena, winning the challenge.
Another one was a distance flying one where, instead of building a glider, he build a rocket car and right before the jump, he blew up his car on purpose and went flying. Like I said, this game may not look stellar, but that's because it's heavily reliant on what demented ideas you put in to it. You can build a car to help you do on foot platforming exploration if you want. The online multiplayer also looks very fun.