Dang you Usonians get computers way cheaper than down under. That said, the Intel 4000 is highly dependent on the rest of the computer, and can either be very bad or very good.
Sonic Generations is an intensive game though - you'll probably want to turn down the resolution, turn off the shadows and reflections, and turn off the analytics tool which for some reason is set to "on" for default and can cause lags on otherwise great hardware.
In addition, you'll want to run the game with the laptop's power plan on high performance (e.g. minimum processor state set to 100%, and active cooling), since it is very processor intensive and doesn't seem to know how to use the processor states effectively (at least on AMD).
Mind you, some people can get the game working on a 3000, but bad frame rate, and others can get it working on a 4000, but with a bit of choking on high settings (e.g. not being able to run it at 1920x1080).