Not bad!
Although the feeling is much different to the gravity gun of Half-Life2.
That has not to be a drawback, but you should exemplify and establish it as a tool on its own, with a different behavior and a different style than that of HL2.

And, you should place only cube shaped objects in the level. For instance the van looks great, but its collision doesn't fit with the shape.

If you want to make it a shooting game or something like that, you should consider what advantage the gravity gun has against a gun, because only if the player gets an advantage a feature, it makes sense to use that feature.

Maybe, the player controls a hero with a strong arm/two strong arms, who can't handle guns or pistols?...