A massive Team Fortress 2 Mann-conomy Update has just added the ability to buy unlockable weapons and items for real money - anything from $0.49 to $4.99. The 17 community-made items the game's just added can still be unlocked for free, but there's no quick or reliable path to do so - unlike the achievement route of previous updates. If you want them soon, you'll have to pay.

TF2 has long been the industry posterchild for ongoing free content: its free updates have added 26 of its 32 maps, 8 of its 10 game modes, and 52 of its 77 weapons. So why start charging now? Team Fortress 2's lead designer Robin Walker offered to answer our questions before the update went up, to help clarify the thinking behind this - the first of three big surprises Valve have planned in the next twelve months.

PC Gamer: Just to be absolutely clear: everything you can buy with real money is also available to find or craft for free?

Robin Walker: Almost everything. There are a really small number of cosmetic items that you can't find. On the flip side, there are a few items that aren't purchasable either. Our main goal was to make sure that all gameplay affecting items are findable, so that no-one can buy an in-game advantage over someone who's choosing to find their items.

PC Gamer: Are the new items in this update just the Polycount ones?

Robin Walker: We're releasing a lot in this update. It's roughly the equivalent of 60% of the items we have released in the 120+ prior updates.

The Polycount items equal about five new class updates. There are a bunch of cosmetic items for all the classes, some built by us and some by community contributors. Then there are a new kinds of items, like Tools, which are items you use to customize other items. For instance, you could use a Name Tag to permanently change the name of one of your other items, or you could use a Paint Can to change the color of your favorite hat.

PC Gamer: Can you give a couple of examples of new subclasses created by the new items?

Robin Walker: The new Spy set is interesting. Your Eternal Reward allows you to get utterly silent kills on enemies, but removes your ability to disguise at will. This forces you to rely on cloak much more, and to de-cloak for the kill as late as possible. When you kill someone their ragdoll vanishes almost instantly, and you automatically become disguised as them. There's a wide ranging set of ways this combination of effects changes the Spy, from the fact that sentry guns become more of an issue, to you needing to find a lone enemy for your first kill (because you won't be disguised when you get it). The fact that the set doesn't include a specific invisibility watch means you're free to experiment with any of the three existing watches to see which cloak works best for you. The Dead Ringer's an interesting match, creating a Spy who's unable to cloak or disguise at will.

My personal favorite is a Sniper subclass that I haven't figured out a name for that isn't borderline offensive. It's The Huntsman, Jarate, and The Bushwacka. I play it as a front line combat class, using the Huntsman at first. As soon as enemies start to close, I throw the Jarate and flip to the Bushwacka to use its critical hits for a melee kill. It's too dangerous to be consistently effective against skilled enemies, but it sure is fun to surprise people who expect Snipers to always retreat.

PC Gamer: What are item sets and what's the benefit of them?

Robin Walker: An item set is a group of items for a single class. When all the items in the group are worn at the same time, the wearer receives additional bonuses (and sometimes penalties). For instance, the Soldier's Tank Buster set includes three items - The Grenadier's Softcap, The Black Box, and The Battalion's Backup. When all three are worn, the set provides an additional 20% resistance to sentry gun damage.

Item sets are an interesting design tool for us. At a high level, they allow us to embody the concept of a subclass into a set of items, which helps to identify that subclass to players. They also allow us to increase the cost of switching out one item for another, in that a player would really like to wear the whole set to get the extra bonus, so swapping any one of those items out for another one has an additional cost. That cost is a useful tool for us when balancing a set item versus the other items available for that loadout slot. They also provide an incentive to use our new trading feature: if you find one of the set items, you're interested in finding someone who's got a spare of another item in the set.

PC Gamer: What are the minigames? How and when are they played?

Robin Walker: We'd been kicking around ideas for game modes for a while now that weren't really game modes in the way we've used them so far. We've been calling these ideas "minigames" because they're either shorter than a usual TF2 round, or they involve less people. Some of them have the nice characteristic of stacking on top of whatever game mode is being played.

The first one we're shipping in this update is called the "Dueling Minigame". It's activated by using an item that lets you pick a player on the enemy team. If the enemy accepts, the game will consider the two of you in a duel. You'll see your duel partner highlighted when he's onscreen, and the game will track the times in which the two of you kill each other. At the end of the round, the player who got the most kills wins the duel. Players are then given a Dueling Medal item (or if they have one, it's updated instead) which keeps track of how many duels they've participated in, who their last duel was with, their win/loss ratio, and so on. Winning more duels causes your Dueling Medal to level up, and reward you with an item.

The reason we chose this one is because we've found it's a fun addition to any game where you're playing with a friend on the enemy team. Most of us have experienced that slight change in gameplay that occurs when you're being dominated by an enemy player, and the way it causes you to focus on them whenever they're in sight. Duels are a fun way to build on that experience. Our internal play tests often have multiple duels being fought at once as rivalries from previous play tests get refreshed.

PC Gamer: How do you find crates and what do they contain?

Robin Walker: Mann Co. Supply Crates are found only through playing the game, and require a Mann Co. Key to open them. Each crate contains one item from a list of potential items, which you can see in the crate description. They also have a chance of finding items with custom effects on them, which are the rarest items in the game right now.

PC Gamer: How much do the prices of individual items vary, and what determines which ones are more expensive?

Robin Walker: Pricing is a function of value, but it's not the only variable. We see a wide range of item valuation in TF2, so naturally, our pricing attempts to reflect that. Calculating value is a super interesting problem, and part of what we're trying to learn about from the community and the community contributors. We see content consumption and content creation as being on a much smoother continuum in the future, and need to have good mechanisms for valuing and pricing these across a wide range of items and activities. The area we are going to focus on the most is making sure that people who are contributing content are feeling properly rewarded for their efforts. Everyone wins if we do that properly.

PC Gamer: What's the average ballpark price for an unlockable weapon?

Robin Walker: Thanks to my handy calculator, it looks like it's $1.97.

PC Gamer: You mention old community items won't be available to buy right away - will the existing Valve-made unlockables be purchasable after this update? Can I buy a Camera Beard?

Robin Walker: Valve-made unlockables are purchasable from the in-game store. The community contributed items other than the Polycount items are going to be moving over to the new system as we roll it out.

PC Gamer: Why is the Steam Wallet necessary to buy this stuff?

Robin Walker: We originally thought we'd build a TF2 specific system for handling this, but after further thought we decided it would be a useful feature for our Steamworks partners. We also believe (hope!) that customers will purchase more than just one item, and the Wallet makes repeated in-game purchases a much simpler process.

As gamers who've used these kinds of systems before, we wanted to avoid some things we didn't like. One was being forced to add more funds than we wanted (and seeing purchase prices that didn't seem to match the funding options) and the other was being forced to do conversion into some virtual currency in our heads.

We're not doing either of these in the Steam Wallet.

PC Gamer: Is there a risk that knowing people can just buy items devalues their significance, in terms of being a badge of honour?

Robin Walker: Yes. Our assumption is that customers are very smart about figuring out what the "real" value of things are and responding accordingly. We have to think about this constantly, for example that's why we created "Vintage" items, so that people don't lose the distinction of having acquired items before this update arrived. We expect that "Vintage" items will actually increase in value, because they're all limited editions at this point, so we're essentially bonusing long time players.

PC Gamer: When I asked about the way you give out unlocks before, you said you couldn't just give people what they want right away, because they'd ruin the fun of unlocking it for themselves - "People will eat all the sugar they can until they're sick". For people with the disposable income, doesn't this system permit that?

Robin Walker: The addition of unlockable items to TF2 was about adding longer term goals and rewards for players. The value you place in a reward you receive is a function of the "cost" you paid to get it. The reason we don't give you all the items instantly is because they would have had no cost, and hence, you would value them little. So in TF2, the time you take to find an item is the cost you pay. Not everyone has time, though, and by allowing customers to purchase items directly, we're still not allowing them to avoid a cost. It's just that in this case, the cost is money, not time.

PC Gamer: What was the game mode that didn't make it in, and why was it dropped?

Robin Walker: The new game mode didn't make it in because we simply ran out of time to get it done. So it'll be in the next major update, which isn't too far away. The game mode itself is pretty much done, but we're still working on the new map that features it (although it will work in existing maps). The sixth Polycount set I mentioned last time we talked is also being held back, because it's tied to the new game mode.

PC Gamer: You've said TF2 makes more money than it costs to keep developing - why introduce another revenue stream?

Robin Walker: We never really think about the money TF2 makes when we're thinking about what to do.

In this case, the thing that we are trying to build is a framework for a more robust collaboration with the community on content creation. This has been one of TF2's main drives for some time now. In other games, community creators build content after the release, and it forever remains inaccessible to most players. At the start of this year we unveiled the TF2 Contribute page, which was the first step to moving past that model, pushing community created content into the ongoing development of the game itself.

We view the Mann-conomy as the next, crucial step in the evolution of how communities interact with products. Now they'll not only be able to contribute to the product, they will be directly compensated for their work.

PC Gamer: Will the new items be unlockable by achievements, or only through random drops/crafting/buying? If I don't want to spend any money or idle a lot, can I get all the new weapons as quickly as I could with the Engineer pack?

Robin Walker: The new items are the same as the previous community contributed items we've shipped, in that they're not tied to achievements. We expect people will get the new items slightly faster than previous community items, because in addition to the usual random drops and crafting, there are now more ways you can collect them for free (trading for them, winning duels, receiving gifts).

PC Gamer: How do I go about finding someone to trade with? If I want to swap my Prussian Picklehaube for a Pyro monocle, do I have to go around spamming the chat channel on a bunch of servers to find someone who has what I need?

Robin Walker: You're able to trade with any Steam user, by selecting a friend or someone on the server with you, or by entering a profile URL. We're going to watch how the community uses the feature, and decide what our next step should be. There are already a bunch of great looking TF2 trading webpages that have been waiting for this update to go live, so it'll be very interesting to see what happens.

PC Gamer: The leading theory in the office about this surprise was that TF2 would go free-to-play with item sales to support it - is going free something you considered? What are the chances of it happening in the future?

We've considered it, and it's something we'd love to gather data from, but our main concern is that right now the cost of purchasing TF2 again is the main cost that cheaters pay when we catch them.