Downwell

Hard mode is unlocked after beating the game once. For more information on Hard Mode, see Step 3 of the Roadmap.

The lack of air is now aggravated, as on Hard Mode there are no canisters or shells to break (in or out caverns). Air bubbles are scattered, floating around the stage, and you need to collect them in order to regain oxygen. Also, it depletes faster. Enemies come in greater numbers, jellyfishes and piranhas tend to appear from almost anywhere, and walls and floors are covered with more red spikes.

Contrary to Area 2, here you need to go faster. Kill only if you need to, and try to avoid any enemy you can. If you have the "Knife and Fork" upgrade, then it's time to eat corpses, as they fall slower in water. Laser Weapon and Blast Module do wonders here. Just keep an eye on your bullet count, so as not to run empty in the middle of nothing and a group of piranhas coming to get you.

And one last warning: no matter what, avoid getting the Gunpowder Blocks upgrade. It will destroy entire blocks where you can land, thus making your already hard life unbearable.

The trophy will unlock at the upgrade selection screen of Area 3-3.