Just look at it.
The Super Beetle has a wide hood at the bottom. Kind of like this:
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The standard beetle is more pointed:
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Other basic differences is the position of the spare tire in the trunk. In the Super it lays down flat, and in the Standard it is upright.
The biggest difference is the front suspension. The Standard Beetle has twin torsion tubes going across the front and standard shocks. The Super uses a McPhearson strut system.