Entertaining? Yes. Acting performance? Okayish. Eastwood a bit wooden at times (I love him for that though).
Camera and location? Good! Influential? Even I can see that (cf. the Wolfenstein video game). Good movie? Nah... It's too long. People look too perfect - especially those who are killed or seeing combat. They didn't bother to speak German, although that's a major part of the plan (which is of course dangerous production-wise given that you have to sound like real Germans and almost nobody in filmmaking history ever got that right). It's full of stereotypes incl. cultivated, adventurous and daring British officers with a posh accent, cool Americans, well-dressed, shouting, angry German idiots (who are too easily tricked and killed) with dobermans, klaxons and leather coats. Unrealistic plans (I mean that was the plan? Isn't that unnecessarily convoluted just to uncover a few spies?). Unrealistic coincidences. Unrealistic fights (that's basically another thing the FPS Wolfenstein and this movie have in common). The good guys have a seamingly limitless supply of explosives and ammo, the Germans didn't manage too shoot a single one of the infiltrators. That's not how war works... It's all a bit ridiculous. Add those bombshell blondes and brunettes, a few explosions too many, and they have come damn close to making a Bond movie.