Breath meter

The meter turns on the moment the pixel immediately above your eyes goes under water or honey, and not a moment earlier. That threshold is deliberately forgiving: standing in two full tiles of liquid with the third tile above you clear leaves you breathing normally, which stops you suffocating every time you walk under a low pocket.

It refills quickly once you surface, a little over a second from empty to full, at a fixed speed no equipment changes. Short dips therefore cost you nothing at all, and there is no reason to ration bubbles on a shallow swim.

With nothing equipped you get about 23 seconds. A Breathing Reed doubles that to a bit over 46, but it has to be in your hand rather than your inventory, which is the detail people miss when they wonder why nothing changed.

Diving equipment is the real jump. The Diving Helmet, the Diving Gear it crafts into, and the later Jellyfish Diving Gear and Arctic Diving Gear all give 140 seconds. Hold a reed at the same time and the two multiply rather than add, landing you at 280 seconds. Four and a half minutes is enough to cross an entire Ocean floor and come back without surfacing.

Neptune's Shell and the Moon Shell and Celestial Shell built on it delete the breath meter in liquid outright, with no timer to manage. A Gills Potion does the same for four minutes.

Once you have either, every timed option above is obsolete for breathing purposes. The diving accessories stay worth an equipment slot only for the swimming and the light they carry alongside, not for the air.

There are 200 units of breath and a small counter that has to fill before one unit is spent. Bare, that counter takes seven ticks per unit. A held reed doubles the requirement, diving gear multiplies it by six, and holding both multiplies the two together, which is why the totals compound instead of stacking additively.

The check runs every tick, so swapping gear halfway through a dive changes your remaining time immediately rather than waiting until the next unit ticks over. You can put diving gear on while already underwater and get the benefit at once.

• A Fish Bowl in an equipment slot means your head is underwater as far as the game is concerned, permanently, meter and all. Diving gear and potions still counter it, so it is wearable, just never free.
• The Lava Charm timer draws over the breath meter visually. Stand with your feet in lava and your head in water and you lose breath with no bubbles on screen to warn you, and the first thing you notice is the drowning damage.