Nier: Automata

There is no auto save
You unlock fast travel early, so you may want to do some story missions before going for side quests.
Some attacks aren't obvious. Jump and press Heavy Attack or Pod immediately do a special aerial attack. Heavy attacks vary depending on your weapon.
You don't have to keep pressing the dash button to run fast. You press it for a short while and keep pressing the analog stick in a direction.
Be mindful of enemy levels. You can fight lvl 20 mooks and then suddenly run into a lvl 50 enemy that will mess you up.
Leveling up weapons at weapon sellers can add combos and special attributes to them.
The story isn't finished until you get to ending E.
Don't play the prologue on hard, because you can't save, and dying will make you do the whole thing over again.
There are no difficulty-related achievements.
Almost nothing is missable. You unlock a chapter select after your third playthrough and can redo sidequests you missed.
Dodging at the same time as an enemy attack is called a perfect evade and has a special visual effect. A light attack, heavy attack, or pressing the fire button afterwards will each do a special counterattack.
If you have more than one pod, charge pod program button to use multiple programs at once.
Retrieving someone else's online corpse looks like it gives you chips, but it instead gives you those chip effects as a temporary buff.
Eat the mackerel. Do it.