Regarding not one thing "making or breaking" you. When I went in 2008 we were told the exact opposite - that you had to pass all parts of the selection (tests, computer, group and interview). They explicitly said there was no crossover between the different elements.
Having said that, however, no such thing was said this year. Perhaps things have changed.... The amount of time to get a "yes" certainly has.
Considering that they have considerably shaved the computer testing, I would assume that they do attach an element of importance to the bit they've kept in. Otherwise, they would have removed it all?