Well a shield generator in the game works. In real life I guess you'd put the generator under the shields, logically, so you'd have to brute force your way through the shield, use some kind of anti-shield counter-measures (like Ion Cannons) or wait until they run out of power or something like that. The point in the game is that they force you to zero in on one point of the ship (while the guns are targetting you and firing all around) rather than just letting you shoot any corner of the ship and blowing it up. If you limit your vulnerability to one point instead of all over, that's to your advantage, no?
Now as to the shield generators on the PLANET, that's a different story. They resemble the Gungan theater shields in Episode I. That's the one and only time we've ever seen such shields used in Star Wars that I know of. Again, the generators inside make perfect sense here too. That they stop lasers is fine, since it's much easier to fire long range and destroy targets than to run right up to them and start firing. After all, what's the point of having a good ranged weapon if it can't be used at range? Everyone should switch to lightsabers.