well railgun is more useful against the stronger enemy variants and so yeah but I can still complete most of the game without it but sword needs 3 stone 2 for crucible then one for the steel then I need spear and 2 sticks plus obsidan and ice then fire stone and sand for wetstone and then other things obsidan spear does damage ice frezzes and does dmg sharp sword does mobility and damage and more range railgun is just damage