Q: What's the best version/region to run on?

A: Refer to this. In general though, PAL is the fastest (IGT) and most optimal version.

Q: What's the difference between Portable Ops and Portable Ops +?

A: MPO+ functions as MPO's standalone expansion. While its main additions were focused on expanding upon MPO's multiplayer modes, it also offered new singleplayer content in the form of “Training” mode and the Randomizer-esque “Infinity Mission”.
You can find resources for the game right here.

Q: What systems did MPO release for? What can I run this game on?

A: Originally released as physical UMDs exclusively for the PSP, this game received digital rereleases on both the PSP (currently only purchasable & transferable from PS3 systems) and PS Vita/TV stores.
These versions are identical to their physical counterparts with the added benefit of having much faster loading times due to the game being run from storage as opposed to from a disc.
If you wish to play on an emulator, use the latest version of PPSSPP. PPSSPP versions pre-1.0 are banned outright and versions prior to 1.4 are not recommended due to a potential crash during the Gene fight.

Q: Why is my character facing the wrong way at the start?

A: Holding the analog stick while the map is loading in causes you to face in different directions. It's usually not recommended to do this.

Q: I can't perform a Member Swap, what's happening?

A: You're either not close enough to a hiding spot, you've triggered an alert, or you've raised suspicion in close proximity.

Q: How and when do my soldier's HP and Stamina reach their maximum?

A: After 60 deployments in main missions, your soldier's HP will have increased by 60 and their Stamina by 100.

Q: How to tell if a soldier is worth recruiting?

A: Useful soldiers will either have Magazines, Chaff Grenades or Ga-Ko dolls in their possession. You can make them drop their items or see it in their inventory post-recruitment.
Those who drop/carry Magazines will have greatly increased HP. Chaff G. carriers will have vastly increased skills, including S-Ranks. Ga-Ko fans share both of the mentioned bonuses, but spawn extremely rarely (0.XX% chance).

Q: NG+: Why are my SAA shots not ricocheting off the walls?

A: You need a minimum Handgun Skill of A in order to start having bullets ricochet.

Q: What causes Ghost/Paramedic/Sigint to sometimes initiate conversations when calling them from the Silo Complex?

A: RNG. Though, even after skipping 1 or 2 chats you'll still be saving time compared to manually dialing in the necessary frequencies.

Q: NG+: Why do I play as Snake even though I have other soldiers in the Sneaking Unit?

A: The first two missions force you to play as Snake. All your Sneaking Units will become selectable after finishing Soviet Patrol Base 1.

Q: Why don't we go to Town for the TNT Diversionary Ops?

A: Town is much slower than the other locations due to the requirement of having to destroy 3 targets.

Q: How to increase the odds of receiving Spy Reports? How exactly do Spy Reports work?

A: Your Spy Report acquisition rate is based on the combined Sense stat of the soldiers at your desired location and the overall Spy Unit Level (raised by having other spies in the Unit).
For NG+ runs we use our two best spies, which reach a combined Sense of at least 165 for most of the run. This provides the best balance by having near-guaranteed Spy Reports within 2-3 Waits and not having to spend additional time (~8s) moving around a third Spy.
Even with the highest possible Sense value from Unique Soldiers on one location (100+65+60+60 = 285), getting a Spy Report after a single use of Wait is not 100% guaranteed.

Q: NG+: Why use a third Spy only to leave them at the Research Lab after their report is acquired?

A: Leaving a third spy somewhere in the Unit will significantly improve your Spy Report acquisition rate. This conveniently allows us to do a three-way split for the Diversionary Ops Reports and abandon Spy #3 there to buff the Unit.
Research Lab is chosen, because it will get you one less optional report/notification throughout the run to lose time on and also needs less menuing inputs than Supply Depot and the Soviet Patrol Base.

Q: NG+: Why don't we use soldiers with the Gambler career against RAXA & Cunningham?

A: The Gambler career's buff does not trigger on weapons like the RPG-7 or Stun Grenades.

Q: NG+: Why don't we move a soldier to the Technical Unit earlier/before starting the run?

A: Having the Technical Unit active will start the production of lots of equipment during the run. Once completed, these come along with confirmation boxes which will lose the player lots of time.

Q: NG+: Why should the soldier used for Time Bomb development not have (Elite) Engineer careers or a Technical Skill of S?

A: Both the Engineer/Elite Engineer careers and an S in Technical Skill will lose you time, because the soldier will be producing unnecessary equipment that comes with further menuing timeloss.

Q: Python freezes my gun! What do I do?

A: If he's running up to you, get out of First Person View and dodge his melee attack.

Q: Why is Null blocking my shots?

A: You need to aim towards his lower legs and feet to hit him properly, if you aim too high he'll block it.