Counter-Strike, the culturally-significant decade-old multiplayer phenomenon, may finally be dethroned as the most popular game on Steam.

Valve today has relaunched Team Fortress 2 as a complete free game, in what Valve describes as "the most ambitious update in the history of Team Fortress 2”.

Develop has been given exclusive access to speak to game’s longstanding patriarch, Robin Walker, to discuss the move in detail.

How did the idea of making Team Fortress 2 free-to-play come around?
We've been toying with the idea ever since the Mann-conomy update, where we added the in-game Team Fortress 2 store.

Over the years we've done a bunch of price experimentations with the game, going all the way down to $2.49 in our random one-hour Halloween sales.

The more we've experimented, the more we've learned there are fundamentally different kinds of customers, each with their own way of valuing the product.

Now that we're shipping it, it feels like a fairly straightforward next step along the "Games as Services" path we've been walking down for a while now.

How will Team Fortress 2 be monetised? Just through microtransactions or in-game ads and other routes?
Right now we’re only planning on using the items you can purchase from the in-game store.

Is there a concern that you've let the genie out of the bottle? A triple-A high-quality game for free will change expectations on what you charge for other games, will it not?
We’re always improving on the relationship we have with our customers, and we’re willing to run experiments if we think it will help us learn how to do that better.

Is the free-to-play move motivated as much by a desire to get people to try the game as it is monetary?
Sure. It's a belief of ours that in multiplayer games it's generally true that the more people playing the game, the higher value the game has for each individual customer.

The more players, the more available servers in your area, the wider variety of other players you'll find, the greater the opportunity for new experiences, and so on.

Another way we think of it is that there are a class of players who will never pay us a dime, for a variety of reasons. We're not upset by that, it's just a constraint we need to design around. The interesting problem to solve is how to make those freeloaders produce value for our paying customers. Obviously, getting those free players into the game is the first step to doing that.

Is the wider F2P strategy to get more people to install Steam?
It's another goal, yes. But the main connection between this and Steam is the Steam Wallet, which is Steam's microtransaction system that we're using in TF2.

There are now several other free-to-play games on Steam all using the Steam Wallet too, which creates a nice ecosystem for all of us developers.

Any player who buys something in TF2's store will then be familiar with the purchasing process used in all these other games, and that removes one of the biggest barriers to entry for them buying something in those other games, and vice versa.

Once TF2's online store opened, content updates became more regular. How will the free-to-play model affect the rate of updates?
It won't really change anything there - we've been trying to get faster at content releases, and this simply puts more pressure on us to do that. When we talk to other Free-to-Play developers, they tend to scoff at the slow speed of our updates.

Will there be a slowdown in item drops to encourage more store purchases?
No. Our goal first and foremost is for players to enjoy the game, and we think finding items, and getting to experience new gameplay through them, is one of the things that's really fun in the game. Removing that seems counter-productive.

Purchasing something is a step that we hope players take after they've decided they like the game, not something they should have to do while they're still evaluating it.

You give community contributors a slice of the profits for items they sell, can you give any details on how this works out percentage wise? Will this deal be affected by the free-to-play model?
Many of the new items we release use art assets that were created by community members, submitted to us via our Contribute page. Any time a player purchases one of those items in the Mann Co. Store, we split the sale with the community creator.

We're not making any changes to this now that we're Free to Play. Today's update contains some items that were made by a fourteen-year-old modeller - hopefully he'll be able to make a strong case to his parents for playing more games when his creations pay for college.

Speaking of the community, how do you feel they will react to the change - and to the free-to-play newcomers?
One of the neat things about being live is that we often get to see what customers think of something before we do it.

When we did the Mann-conomy we looked around a lot to see what issues people had with microtransactions, and tried to design a system that didn't have those issues - so we don't have a virtual currency, we let you fund your wallet with exactly the amount you want to spend, and we don't force players to "pay-to-win".

For free-to-play we looked for two kinds of feedback: what customers issues were with free-to-play games, and what fears our existing customers had with the idea of TF2 becoming free.

The primary concerns of our existing customers were that the game would be overrun with cheaters and griefers, and that we might start charging our existing customers for ongoing use of the product.

We're not doing any kind of subscription, nor are we taking any features away, so the second one is easy.

For the first, we're as concerned about cheaters and griefers as they are, so we've spent a bunch of time trying to figure out all the ways that griefers can hurt other player's experiences.

It's a tricky problem, because any feature that can be used for griefing might also be the feature that convinces new players that the game is worth their time.

For example, in-game voice chat can be a tool for evil, but it can also be an awesome tool for making new friends.

We're never sure that a decision we make without data will be a good one, so what we've chosen to do is ship with these kinds of features initially available to free customers, but with a system where we can them off from the backend.

So if we see that one of these features is turning out to be a net negative, we'll be able to easily remove it from free customers.

You have previously said that you track people who load TF2 up once, and then never play it again. How do you think free-to-play will affect this kind of behaviour?
Our prediction is that we'll see an increase in the percentage of customers doing that, because free players have invested less before they try out the game.

But we think that kind of dropoff is something we tackle more with education, which is why we've now built a detailed tutorial, and added an Offline Practice versus bots mode for new players.

QuakeLive has always been free-to-play but struggled to sustain itself and had to introduce a ‘pro’ membership subscriptions. Is this a possible avenue for TF2?
Subscriptions aren't something we've really spent any time thinking about. With existing customers being one of the primary sources of value for new players, we'd like as few barriers to them sticking around as possible.

Finally, will other existing Valve games become free to play?
The data we got back from the Mann-conomy Update leads us to believe that TF2 would be more successful as a completely free product.

With just the data from a single product, it seems dangerous to assume that it would be true for all our products.

Either way, we'll know a heck of a lot more in a couple of months, and that's the kind of thing that gets us excited around the office.

[Editing/questions by Lewis Tyler]