I suppose given that Natsu no Arashi (rather bizarrely) began with a filler episode, it's only right and proper that it should end with a filler episode too - What do you know, that's exactly what we get, complete with plot aspects that you won't be entirely unfamiliar with if you've seen that opening instalment.
Of course, this series wouldn't be daft enough to bring us an entire episode based around a strawberry "bomb" again, oh no.... This time it's a cherry "bomb". Thankfully there's more to this episode than just that, with the now almost infamous discussion about spoiled milk and what happens to it if you take it back in time reaching new and even more mind-bendingly hilarious heights. That aside, we're also granted the sight of the main cast members in a number of ridiculous (and a few rather alluring) costumes, for reasons that are probably beyond explanation (although Jun certainly reverting to dressing like a girl at the cafe goes equally unexplained, which to my mind is a far bigger question).
It's difficult to know what to say about this episode beyond these rather oddball goings-on, which mix in with the occasional jump through time to close out the series in a way that I suppose I can only really label as "different".
I suppose "different" is probably a pretty decent label for Natsu no Arashi as a whole, being as it is a series that has little difficulty in breaking with convention. Indeed, this show almost constantly felt like it didn't know what it wanted to be, moving from comedy to a very different take on time travel through to the horrors of war in a surprisingly effortless (and occasionally effective) way - These constant switches arguably made the series a jack of all trades and master of none, but you have to give it points for effort if nothing else. Above all, Natsu no Arashi will probably live long in my memory for a depiction of wartime Japan that was the most beautifully and starkly rendered since Grave of the Fireflies (albeit in a very different way, of course) - Seeing the horrors of firebombing raids through the eyes of first Hajime and later Jun were harrowing yet incredible moments that really defined this series as more than a fun little comedy series, and some of the human aspects of the war which went alongside such scenarios were also well played.
Those juxtapositions of comedy and seriousness, mixed in with Shaft's unique visual style, really does mean that Natsu no Arashi defies summarising in a snappy and concise way - Thus, I'm not even going to try; it's a fascinating series that you really have to experience for yourself to cast any kind of judgement on.