After a few more days, I've noticed some more things.
You can't see your body when you look down. It's a small thing, but I was disappointed for almost a minute. I assume this is what is happening:
Another thing is, if you don't look at the achievements list, you'll likely not get a lot of them. Of course, this doesn't bother me, since I'm going to do a second playthrough regardless.
The sniper rifle is USELESS. There are literally zero chances to use it, since it's LOUD AS FUCK and can't be silenced. I opted to use the far more common revolver and shotgun, as they take up the same amount of space in my inventory. It's a shame I didn't realise this sooner, as I upgraded the sniper rifle's ammo capacity a bit before realising I never use it. I use my pistol for the same job, as it's silenced and accurate as fuck.
Also, speaking of shotguns, this is literally the third game I've ever played with a useful shotgun, RE4 and RE5 being first and second. San Andreas is arguable, as the SPAS12 is pretty nice, but by the time you get it, it's outclassed as fuck by the M4 or even the fucking AK-47.
Exploration is my favourite thing about this game. You get experience for finding hidden areas. There are multiple paths into nearly everywhere.
JAKEY'S GUIDE TO AUGMENTATIONS
CASIE speech app (allows you to mold people's emotions in your hands like fucking putty; also gives Malik some funny lines)
Hacking lvl. 2-5 (you NEED to be able to hack into armouries and labs)
Hacking stealth (hacking level 5 is SHIT if you get detected by the system)
Increased inventory space
Dermal armour (increased damage resistance)
Heightened lifting ability (a lot of vents are hidden behind vending machines, crates, etc.)
Icarus landing system (allows you to jump off ANYTHING and live; useful for elevator shafts)
Heightened jumping ability (allows you to jump super-high)
NICE TO HAVE:
More energy (allows you to do more spy shit; takedowns, wall-punching, etc.)
Rebreather (allows you to breathe in poison gas with no problems)
Punch through walls (some walls can be punched through, but I haven't gotten anything AMAZING because of it)
Radar upgrades (allows your radar to have a longer range and more information; not bad at all)
Reflex booster (allows you to melee takedown two guys at once; not essential but useful nonetheless)
Stealth enhancer (basically displays stealth-related information on the radar)
Cooldown timer (shows when guards will give up looking for you)
Sprint enhancement (allows you to run faster)
EMP shielding (makes EMP grenades/electricity not drain your energy; electricity still drains health)
Energy recharge rate (it recharges fast enough, and you get loads of instant recharge bars)
Sprint for longer (nice for town hubs, but useless in actual missions and shit)
NOT TOO GREAT:
Recoil compensation (I never really noticed recoil to begin with)
Arm stabiliser (Jensen's arms don't flail about when he tries to shoot like, say, RAIDEN)
Hacking fortify (I have never fortified anything ever; stealth makes this obsolete)
Hacking analyse (by the time you even consider this, you won't need it)
Flash supression (hardly anyone uses concussion grenades)
STOP CLUTTERING MY FUCKING SCREEN:
Cloaking system (makes you invisible for a bit)
Smart vision (allows you to see through walls. SHIT)
_________ silently (allows you to walk/run/sprint/jump/land/have a cup of tea silently)
Typhoon explosive system (subtlety is all but lost when you have this)