ETG is very fast paced a tip would be know hod to dodge roll theres a mechanic there that makes you immune for a few seconds to any damage even contact. But remember this never dodge away from the bullet in which its traveling to dodge into or the sides, the dodge could also be used as contact damage too but only if you know the enemies HP in which you could use that, only really useable against the smallest slimes really in cases you back into a wall and reloading your weapon. You start with one Key on any Gungeoner, save that key if you run into the first chest on the floor dont get too happy and open immediately, chances are the second chest could be better. I think dark chest is better then royal red to green to blue to brown. Brown chest usually have keys tho sometimes. On each floor you will get one weapon and one item from the 2 chest. Usually theres a secret wall inside the chest room use a gun that has limited ammo to shoot either walls thats seems to have a open path behind it if you see a crack you could blank it to open a secret room containing mostly a chest sometimes just ammo pick up or a heart. After defeating the boss if you still have blanks and shot all suspecting walls for the secret room go blank the shop room chances are its there. Choose which gun you want to use as a room clearer and a boss killer you will eventually memorize which is your fav. Also learn as you go it ok to make mistakes. But yea so far these should be good enough to help you out as a new comer to the game. Also to add just so you know if you kill a boss without any damage taken you get a extra heart container for it which is very useful.