It's too similar to number one: diggers still fail to work successfully, and are hard to manipulate, as is the case with many contraptions, still way too confusing because there are so many dials and options, and it can be difficult to navigate around the controls when building, for example, if you have many contraption parts which cross over, and you want to connect via a joint, you sometimes have to click through the options for ages. 2/5 at best
Ok now I've played the game, so I know what to say.
1) Limited monster types/grapihics, they're just shapes.
2) Takes Ages to actually set up the level order because, for some reason, the game randomises it.
3) Tower types are limited
 "Four Second Firestorm"){kind=icon}
 "Warzone tower defense"){kind=icon}
 "Pandemic: American Swine"){kind=icon}
 "GeoSketch"){kind=icon}
 "IncrediBots 2"){kind=icon}
 "Doublue Wires"){kind=icon}
 ">> Musik Marathon <<"){kind=icon}
 "Dynamic Systems"){kind=icon}
 "Phlocks"){kind=icon}
 "Cargo Bridge"){kind=icon}
 "Atomik Kaos"){kind=icon}
 "PingBall"){kind=icon}
 "Shopping Street"){kind=icon}
 "GemCraft chapter 0"){kind=icon}
 "Create your own TD 2"){kind=icon}