Free games. When Sony asks you to lay down $50 for a PlayStation Plus subscription, it says a bunch of free games are part of the bargain. How many do you get? Are they good, current titles? Are they unknown indie experiments? Are they retreads living off an old reputation?

Polygon is looking back on the year in free games with an in-depth series today picking apart both the dollar value of free games given out by PlayStation Plus and Xbox Live, and the critical score of each game on offer. First up is the first service to offer the incentive: PlayStation Plus, which in 2015 gave out 72 discrete titles — six per month — for three platforms: PlayStation 3, PlayStation 4, and PS Vita.

All told, a $50 PlayStation Plus subscription in 2015 returned $1,053.36 in games to a subscriber who had all three platforms. This monetary figure counts the same title on multiple platforms only once. (For example, a game on both PlayStation 3 and PlayStation 4 that costs $20 on each platform counts only $20 toward this total, not $40.) The prices are for the digital version of the game on the PlayStation Store as of yesterday.

Getting Started

Counting each version as an individual game, PlayStation Plus offered 108 games offered for free on three platforms in 2015, and they averaged a rating of 75.5.

Our reasoning is that, when assessing the monetary value of a free offer, one title should count only once, particularly as PlayStation Plus has many cross-buy titles where acquiring a game on one platform entitles the owner to the same game on another. When assessing the critical reception of a game, however, the experience and quality can be different from platform to platform. So in averaging critical scores each platform appearance of a game is treated as an individual game.

This dual standard is in place to prevent multiple copies of a game from inflating the value of the subscription, while also ensuring ensure that the entirety of this catalog's critical merit is reflected.

What about Xbox Live Games With Gold?

• That analysis is here.

With all that out of the way, let's break down what PlayStation Plus gave away, month-by-month, how good it is and how much it really costs.

January

Infamous: First Light (PS4)

The Swapper (PS4, PS3, PS Vita)

Prototype 2 (PS3)

DuckTales Remastered (PS3)

Duke Nukem 3D: Megaton Edition (PS3, PS Vita)

Woah Dave! (PS Vita)

Average score: 76.6

Total value: $93.27

Skinny: The biggest names here didn't do so well with critics, but their high price points made for a solid month

February

Transistor (PS4)

Apotheon (PS4)

Yakuza 4 (PS3)

Thief (PS3)

Rogue Legacy (PS4, PS3, PS Vita)

Kick & Fennick (PS Vita)

Average score: 80.5

Total value: $107.94

Skinny: PS Plus's second-best month by critic score — which is saying a lot considering Thief is on the list.

March

Oddworld: Abe's Oddysee — New 'n' Tasty (PS4)

Valiant Hearts: The Great War (PS4)

Papo & Yo (PS3)

Sherlock Holmes: Crimes and Punishments (PS3)

OlliOlli2: Welcome to Olliwood (PS4, PS Vita)

CounterSpy (PS4, PS3, PS Vita)

Average score: 76.3

Total value: $93.27

Skinny: No triple-A names but still a good month to broaden one's horizons, starting with OlliOlli2.

April

Tower of Guns (PS4, PS3)

Never Alone (PS4)

Dishonored (PS3)

Aaru's Awakening (PS4, PS3)

Killzone Mercenary (PS Vita)

MonsterBag (PS Vita)

Average score: 70.25

Total value: $93.69

Skinny: Despite the low money and Metacritic totals, Dishonored makes this one of the best months for PS Plus.

May

Guacamelee! Super Turbo Championship Edition (PS4)

Ether One (PS4)

The Unfinished Swan (PS4, PS3, PS Vita)

Race the Sun (PS4, PS3, PS Vita)

Hohokum (PS4, PS3, PS Vita)

Murasaki Baby (PS Vita)

Average score: 75.8

Total value: $84.94

Skinny: Critically acclaimed indies means another high Metacritic but a low MSRP.

June

Metal Gear Solid 5: Ground Zeroes (PS4)

Skulls of the Shogun: Bone-A-Fide Edition (PS4)

Super Exploding Zoo (PS4, PS Vita)

Futuridium EP Deluxe (PS4, PS Vita)

Call of Juarez: Gunslinger (PS3)

Cloudberry Kingdom (PS3)

Average score: 72.75

Total value: $76.44

Skinny: Somehow the collective price of games went even lower during E3 month, typically a dry period for the industry.

July

Rocket League (PS4)

Styx: Master of Shadows (PS4)

MouseCraft (PS4, PS3, PS Vita)

Entwined (PS4, PS3, PS Vita)

Rain (PS3)

Geometry Wars 3 (PS Vita)

Average score: 70.7

Total value: $89.34

Skinny: Rocket League is probably the story of free games for 2015, if not the story of sports video games and indie games for the year, too. Surrounding it with no-names like Entwined and Rain makes its debut look even larger.

August

Lara Croft and the Temple of Osiris (PS4)

Limbo (PS4)

Sound Shapes (PS4, PS3, PS Vita)

Stealth 2: A Game of Clones (PS4, PS3, PS Vita)

God of War: Ascension (PS3)

CastleStorm (PS3, PS Vita)

Average score: 80.6

Total value: $73.58

Skinny: Limbo, and a Stealth 2 that reviewed far better on Vita than consoles, helped August to the best critical month on offer from PS Plus.

September

Grow Home (PS4)

Super Time Force Ultra (PS4, PS Vita)

Xeodrifter (PS4, PS Vita)

Twisted Metal (PS3)

Teslagrad (PS4, PS3)

La Mulana (PS Vita)

Average score: 77.6

Total value: $81.94

Skinny: Super Time Force Ultra continues the PS Plus trend of higher-rated indies propping up better-known names, such as Twisted Metal.

October

Super Meat Boy (PS4, PS Vita)

Broken Age (PS4, PS Vita)

Unmechanical: Extended (PS4, PS3)

Chariot (PS3)

KickBeat (PS3, PS Vita)

Kung Fu Rabbit (PS3, PS Vita)

Average score: 76

Total value: $79.03

Skinny: Broken Age and Super Meat Boy deliver big value, the rest are brand-X freebies.

November

The Walking Dead: Season 2 (PS4)

Magicka 2 (PS4)

Mass Effect 2 (PS3)

Beyond Good & Evil HD (PS3)

Dragon Fin Soup (PS4, PS Vita)

Invizimals (PS Vita)

Average score: 70.4

Total value: $101.08

Skinny: How this month only averages a 70 with Beyond Good & Evil, The Walking Dead and Mass Effect 2 is chalked up to the straight garbage dumped on the Vita. Without the handheld it's probably the best month among PSN and Xbox Live for the year.

December

Far Cry 3: Blood Dragon (PS3)

Freedom Wars (PS Vita)

Gauntlet: Slayer Edition (PS4)

King's Quest — Chapter 1: A Knight to Remember (PS4)

Rocketbirds: Hardboiled Chicken (PS Vita)

SSX (PS3)

Average score: 76.6

Total value: $89.94

Skinny: SSX is a great seasonal play and Gauntlet and Far Cry 3: Blood Dragon help send PlayStation Plus out of 2015 on a very strong note.

Wrapping it up

Both the per-game average cost and rating are dragged down by the PlayStation Vita, where Sony experiments with a lot of indie titles and novelties. The two consoles averaged 75.7 in rating and $15.25 per title otherwise yet both figures are still lower than those for the two consoles in Xbox Live's Games With Gold program, which trends more toward established titles or those that otherwise have higher price points.

PlayStation Plus still delivered triple-A hits that were worth it on their own, like Dishonored and Mass Effect 2. It introduced subscribers to some beautiful and acclaimed indie games they may not have chosen to buy otherwise, like The Unfinished Swan and Papo & Yo. And it was the stage for one of 2015's biggest breakout hits, Rocket League. Gamers are conditioned to be a cynical bunch, especially when it comes to big publishers and console makers peeling off digital copies of older games, but this year held strong value for PlayStation Plus subscribers, particularly those looking for new experiences.

By the numbers

Average score: 75.5

Average price: 14.63

Total value: $1,053,36

PlayStation 3: 75.8 Metacritic average, $15.05 per title

PlayStation 4: 75.6 Metacritic, 15.43

PS Vita: 75.06 Metacritic, $13.16

Highest rated PS3 game: Mass Effect 2 (94)

Highest rated PS4 game: Limbo (90)

Highest rated Vita game: Broken Age and Stealth 2 (90)

Highest price PS3 game: Prototype 2 ($39.99)

Highest price PS4 game: Styx: Master of Shadows ($29.99)

Highest price Vita game: Broken Age ($24.99)

Lowest rated PS3 game: Aaru's Awakening (59)

Lowest rated PS4 game: Dragon Fin Soup (47)

Lowest rated Vita game: Dragon Fin Soup (47)

Lowest price PS3 game: Kung Fu Rabbit ($4.99)

Lowest price PS4 game: Grow Home ($7.99)

Lowest price Vita game: Kung Fu Rabbit and Woah Dave! ($4.99)

Metacritic ranges

90 and up: 4 titles

80 to 89: 30

70 to 79: 53

60 to 69: 15

59 and below: 6

Price ranges

$25 and up: 3 titles

$20 to $24.99: 3

$15 to $19.99: 18

$10 to $14.99: 50

$5 to $9.99: 31

$4.99 and under: 3