To be fair, you're locked to a grid in Gyruss and can only shoot approaching critters too, it's just that the grid is invisible and also doesn't change--it's always the same circle-like grid, versus Tempest's more varied webbing. Honestly, I don't see how Gyruss can be seen anything other than a simpler Tempest--it's the same concept, just distilled, i.e., no zapper-like kill everything construct, just regular shooting. It's sort of like the polar opposite of how Arkanoid evolved the Breakout formula, Gyruss kind of simplified the Tempest formula. Interestingly, both took different approaches to similar ideas and both ended up standing on their own as classics for it.

In any case, I agree that games like Axis Assassin and Beamrider were certainly more direct translations of the concepts in Tempest, among all the other clones...