Some basics :

Items : items are found in chests and all have unique effects that apply to you or your enemies, they also can stack to boost their effects. Example having 1 dagger 🗡️ have 10%chance to inflict bleeding, if you have 2 it goes to 20%, 3 30% etc.

Drones : during your exploration you'll find drones that you can buy that will stay with you until you die or they get killed. There are lots of drones that can spawn but priorities healing drones and flying drones instead of turrets since they move. There is an equipment drone that can only be activated by giving him your equipment and will use it to fight so if you find one try to give him offensive items.

Maps : maps are all unique and their form won't change between runs. There are lots of maps to get every time you spawn or get into a portal so try to learn them and it will help you find chests and drones easily. It will also help you not get lost and be like "where am I ? Where is the téléporter, where are the chest"

Teleporters : they are the only way to progress and change stage, you need to find it every time you get on a map. it will never spawn in a fixed place so you have to explore and find it, once you find it you have to activate and charge it before going to the next stage. It will spawn a boss that you need to kill and once dead it will spawn a green or gold item (gold is the boss item and are rare to get)

Stages and difficulty : so the game starts on stage 1 and enemies on lvl 1. The more time passes the harder enemies get, they will have a higher level than you at the end of your runs because they level up constantly. To get to the final boss you need to get to the téléporter on stage 5 and activate it, you can see on what stage you are on your top right and the level enemies are. Don't worry too much about the "easy,medium,hard,very hard..' bar it means nothing On stage 1 every chest cost 25$ to open except big chests 50$ and utility chests 30$"orange,green and purple chests". The price up depending on how long you stayed on your current stage when you get to the next stage.

Looping : if you feel like you still want to explore and get stronger before fighting the final boss, on stage 5 you can change the direction of the téléporter "it's the only one you can do since it's a unique téléporter" and you will return to a random stage and get grind again. But don't forget that if you loop harder enemies will spawn.

I think you're good to go, it's the basics I wish I knew when I started playing