Seems I haven’t played this in a while, and, with Spider-Man 2, Advance Wars: Dual Strike, Pac ‘n Roll, and Osu! Tatakae! Ouendan all out of the way, I thought I’d best return to it.
And it is still too hard. I managed, after several attempts, to get past the first lot of Blue Dark Nuts, only to find a second lot almost immediately afterwards. More, in fact. Spent ages regaining bombs and health, only to die again. And again.
Decided to have a wander instead, and found the Power Bracelet, and a shop selling a Blue Ring. I think the blue ring reduces my damage taken, but I’m currently 10 rupees short of the 250 rupee asking price, so I couldn’t buy it.