It seems I hadn’t actually completed this previously. I thought I had, but it seems I’d only reached level 60-something. Obviously, I then had to do something about that!
So I did, and lo, I completed it. Level 87 seemed to be the hardest one in the whole game (I died completely there several times), with 89 being mercifully easy (I didn’t have any spare bombs or lives at that point). What aceness. I even managed to net two more achievements today. Go me!
After all that excitement, I had a go on Tally Mode, but I’m not sure of the point. You play one level, then stop? Then play the next? But you get scored on a per-level basis? I don’t understand why.