The difference between a gun and a tube in Abyss is that guns are used to catch fish and fight hostile creatures, while tubes handle underwater mobility and oxygen, and are required to safely reach deeper, higher-pressure biomes.

No, Potions and Oxygen Pods work differently, Potions give temporary stat buffs like extra XP or Gun Damage for 15 minutes, while Oxygen Pods instantly restore oxygen rather than boosting a stat.

Star Shards are used to reroll your Race in Abyss, with each Race offering its own passive bonus, like extra XP or Drop Luck.

Getting access to the game's top-tier gear, Ruined Gun and Ruined Tube, normally requires reaching Level 35 and completing both the Lost Captain and Lightkeeper questlines to unlock the shop that sells them.