Prey (2017)

Do the main quest line until you get the Psychoscope so you can start researching Typhons, once you get it explore wherever the hell you want. Talos I is fairly open with only a few plot related gates.

Even before you get the Psychoscope, you can still track enemies on your HUD by zooming in on an enemy for a few moments, which can help you sneak around them more easily.

Get the Materials Expert ("increased recycling yields") and Suit Modification (inventory size upgrade) neuromods ASAP.

The necropsy talent is useless. Only one thing uses the exotic materials to be made, and it requires all resources. Exotic will never be your bottleneck.

You can take 2 alien mods and the game will still 99% treat you as human. Nothing real content changing. Once you get 3 the robots will turn hostile on you. The turrets kinda suck anyway though, so them being an enemy is at worst an inconvenience.

The two most useful Typhon abilities are Mimic Matter 1 and Psychoshock. Mimic Matter is used to get into rooms with the indestructible slats with the small opening at the bottom or stuff where it's too hard to aim with the nerf gun. Psychoshock is useful against the stronger Typhons as it disables their psi-abilities AND makes them susceptible to other damage types.

You get a better pistol (that is still silenced, it just doesn't say it is) if you do an incredibly on-the-way sidequest (On the Talos I Bridge). So max out the starting pistols damage for sure, but maybe nothing else. You eventually get enough upgrade kits to max everything you want, but not at the speed you wish when you dump 10 of them into a quickly obsolete weapon.

The shotgun, on the other hand is close to, if not the, best gun in the game. Upgrade its damage, then everything else ASAP.

The nerf gun can be used to interact with computers and override buttons from a distance and through broken windows. It is also amazing for getting one [baddie] to come to a corner you're behind so you can attack them one at a time, instead of fighting four of them at once. This applies to literally every enemy. You can get away with some real dumb stuff with the nerf bow.

The Disruptor Stun Gun is terrible without Weapon Upgrades, but really strong with them. It isn't just for robotic enemies, it can stun most organic enemies too, and stunned enemies take extra damage.

Recycle grenades can be used to bypass objects that have a Leverage requirement.

In the early game, neuromods are in short supply. This changes gradually (you will soon be able to fabricate them), so don't fret about choosing one upgrade over another (you will not get enough to take everything, however). Some that I would suggest getting sooner than later are the first suit upgrade as your inventory gets full pretty darn easily and there isn't always a recycler nearby, and the one that gives you more materials from recyclers.

Combat Focus is one of the best skills in the game. It gives you bullet time and 20 seconds is a lot longer than you think in a firefight.

Sometimes, when you complete a substantial plot-related objective, enemies spawn in areas you've cleaned out. Don't just dash for the recycler/fabricator to unload, thinking the path will still be clear.

Moving while crouched makes it really difficult for enemies to detect you. Combine this with the "lean from cover" buttons and the silenced pistol, and you can end a lot of fights before the enemy can figure out where it's being fired on from.

Don't be stingy with suit repair kits. You'll be swimming in them by the end of early-game, and having a fully-repaired suit can and will save your life.

Don't feel like you need hacking in the early game. Maybe take level one for access to some loot that will make your life easier, but just about any door/safe/whatever you don't have the skill for will still be there later. Make a note of where things you can't open are and revisit them later.

Mooncrash

The contents of things don't change until you reset the simulation. Stuff you leave on the ground (usually) and stuff you put in containers will remain there for any character you play that run.

Enemies *mostly* don't respawn until the corruption hits a new level. Exceptions that I have noticed are when extra challenges are introduced. As your corruption level is consistent between characters that means that if you've cleaned an area on one character and start another run without resetting then those cleaned areas will stay clean, presuming the corruption doesn't increase in the meanwhile.

Since only one character can hack and only another one can repair things (weapons/doors/etc) you'll want to run them first on any sim to get as many things hacked/repaired as you can before you finish their go. At least one escape method will likely depend on at least one of those two things.

Better grades cost the same the fab, but not to bring in at the start. The fab programs also decide what you can start with at the beginning.