CONTAINS STRATEGIC SPOILERS
This is a strange little comedy-thriller which actually feels like two radically different movies randomly spliced together - and that's because it is: all the scenes of Eddie Murphy clowning and motormouthing were shot afterwards and shuffled in, despite them apparently taking place two years after the Dudley Moore scenes. So you get captions alternating "California: 1982" and "Kuwait: 1984" for each sequence, with the result that the film's timeline bounces back and forth between 1982 and 1984, and at no time do the stars of either section ever meet. It's a mess.
Of the two strands that make up Best Defense (yes, the UK DVD annoyingly uses the American spelling), the Dudley Moore material is easily the better. Moore is an engineer working unsuccessfully on a tank guidance system; he inadvertently obtains someone else's design (before they're murdered by Russian agents) and then has to act as bait so the Feds can capture them. But the device won't work.... Two years later, Eddie Murphy is in charge of the prototype tank which goes haywire and veers off into an Iraq invasion of Kuwait that wouldn't actually happen for another six years.
In fact the two plots are actually put together pretty well, and even though the stars remain separate throughout a bizarre suspense develops regarding how 1984's events will be determined by 1982's. Billed as "Strategic Guest Star", Eddie Murphy is doing the standard early 1980s Eddie Murphy thing, which I never really warmed to, but the real joy of the film is actually Dudley Moore. He may just be doing the standard Dudley Moore thing but, even with a duff script that's palpable nonsense from start to finish, he's got more natural comedy in him than Ferrell, Sandler, Rogen, Galifianakis and chums put together. And it shows.
It's also nice to see Kate Capshaw, Helen Shaver, Tom Noonan and George Dzundza showing up in supporting roles. And it's funny enough: certainly not hysterical but there are more honest laughs than today's comedies without resorting to grossout knob and poo gags or pop culture references. Surprisingly, given the structure, it kind of hangs together and ends up reasonably amusing. I guess that's as much as you can hope for these days.