CHEM RESISTANT - lvl16; req: Medicine 60, ranks: 1
Effects: 50% less chances of getting addicted to drugs
Additional info: Pointless perk, because as I've mentioned many times before the results of getting an addiction are way "smoother" than in previous "Fallout" games. Furthermore, you should have a fairly strong character by now that won't need to rely on drugs in order to win battles.
ACTION BOY / ACTION GIRL - lvl16; req: Agility 6; ranks: 1
Effects: 25 additional action points during V.A.T.S. battles
Additional info: This is by far the most interesting perk you can get your hands on after reaching level 16. 25 points will make a huge difference, especially when using Small guns and Melee weapons. In most cases you'll get one extra attack per turn. Choose this perk as soon as you have the chance
BETTER CRIITCALS - lvl16; req: Perception 6, Luck 6; ranks: 1
Effects: Critical hits take 50% more damage (when successful)
Additional info: It's not a coincidence that this perk appears so late during the game, because so far most of the headshots ended with an instant kill. You may have discovered recently, though, that more powerful enemies require you to fire at their heads at least twice. I would recommend that you reconsider purchasing this perk, however it's not a necessity.
INFILTRATOR - lvl18; req: Lockpicking 70, Perception 7; ranks: 1
Effects: One more try to open a destroyed lock
Additional hit: Useless perk unless you weren't careful in the past. As long as you were thinking of what you were doing, you shouldn't brake any locks. Take this perk only if you know that you've accidentally destroyed a lock to a very valuable treasure.
COMPUTER WHIZ - lvl18; req: Science 70, Intelligence 7; ranks: 1
Effects: One more try to break into a computer system using your Science skill
Additional hit: Similar idea to the Infiltrator perk, however this time you are given one more chance to hack into a closed system. I assume that you were careful and cancelled your login attempts before clicking on the last word. This method prevents the system from being locked down.
PARALYZING PALM - lvl18; req: Unarmed 70; ranks: 1
Effects: Ability to paralyze an opponent for 30 seconds using a special unarmed attack
Additional hit: Interesting perk, but once again - not practical. The main disadvantage is that you'll have to acknowledge a lot of restrictions - you can't use any weapons (only knuckles) and you must activate V.A.T.S. module. If you're still interested go ahead and try - you'll be pleasantly surprised. :-)
CONCENTRATED FIRE - lvl18; req: Energy weapons 60, Small guns 60; ranks: 1
Effects: Each successful hit increases a chance of the next one by 5%
Additional hints: I guess you may have some problems understanding what this is all about. Obviously the best results can be achieved if you hit a target a few times, but I'm sure that most of your enemies die relatively quickly at this point of the game. As a result you may skip this skill and spend a point on something more useful.
NINJA - lvl20; req: Melee weapons 80, Sneaking 80; ranks: 1
Effects: Increased chances of a critical hit by 15% when using Melee Weapons or being unarmed, criticals stronger by 25% when attacking enemy units by surprise
Additional hints: Final perk for a character who wishes to stay in the shadows whenever possible. If you prefer open combat ignore this perk.
EXPLORER - lvl20; ranks: 1
Effects: All primary locations are automatically unlocked
Effects: I would recommend that you cheat a little and save your progress just before you're about to advance to the final 20th level. Once you've done that and chosen this perk create a savegame and go back to the previous save. Results? You won't lose a chance to find out where all the main locations are and you will be allowed to choose a better final perk. Sadly you can't fast-travel to newly unlocked locations - you must get there on foot at least once.
GRIM REAPER'S SPRINT - lvl20; ranks: 1
Effects: Killing an enemy using the V.A.T.S. system replenishes your action points
Additional info: This is by far the best perk you can get in the entire game. I'm sure that you'll find it very useful. The results can only be witnessed when fighting a larger group of enemy units. Eliminating one target will allow you to immediately attack the next one. As a result you will only have to remember about reloading your weapon, so you won't run out of ammo at a crucial moment.
SOLAR POWERED - lvl20; req: Endurance 7; ranks: 1
Effects: Two additional points of Strength and a slow regeneration of health while travelling during the day
Additional info: Interesting perk which may come in handy while exploring the Capitol wasteland. I would recommend choosing Grim reaper's sprint perk instead, however if you don't like to use the V.A.T.S. system, you can take this one.