In true Valve fashion, Gaben & Co. have just launched the long-awaited Source 2 engine… as part of the new Dota 2 Workshop Tools. Oddly, Valve isn’t confirming that this is actually Source 2 — but the Steam and Dota 2 communities are confident that this is it. You can also run an alpha version of Dota 2 in the new Source 2 engine, making it unofficially the first Source 2 game. Officially, we hope that Valve is still holding out for Half-Life 3 as the first real Source 2 game — the math checks out: Source 1 + Source 2 = Half-Life 3. Read on for our early impressions of the Source 2 engine, and how to try it out yourself.

Visually, Source 2 currently looks very similar to Source 1. It appears that some Dota 2 spells have different particle effects in Source 2 and lighting seems a bit fancier, indicating there’s been some underlying tweaks to the engine, but that’s about it. I wouldn’t worry too much, though — as far as I can tell, the Source 2 version of Dota 2 is using the exact same assets as the Source 1 version (yes, this means Source 2 appears to be backwards compatible with Source 1 games). We won’t see any significant visual differences until developers/games target Source 2’s new features. [Read: With a $10 million prize fund, Dota 2 is now one of the world’s biggest sports.]

As for whether Source 2 uses DirectX/Direct3D, or OpenGL, the jury is still out. Historically, Source is a multi-platform engine that uses a variety of low-level graphics APIs. There are some new DLLs in the Dota 2/Source 2 directory that suggest D3D10 and D3D11 are both available. Personally, given Valve’s focus on cross-platform compatibility, the impending SteamOS/Steam Machines, and its declaration that OpenGL is faster than DirectX, I wouldn’t be surprised if Source 2 primarily targets OpenGL. (Though, given the Xbox One’s use of DirectX/Direct3D, there will certainly be a D3D version of Source 2 at some point.)

One other thing worth noting: The Source 2 version of Dota 2 loads much, much faster than the Source 1 version. It also feels snappier. I don’t know if this is entirely due to Source 2 (it could be down to some other changes in this alpha build of Dota 2), but it would make sense if that was the case. I also noticed, by looking at the Windows Task Manager, that this version of Dota 2 uses a 64-bit binary. Source has historically always been 32-bit. 64-bit Source 2 could partly explain why the game feels so snappy.

Beyond the game engine itself, this soft-launch of Source 2 also includes a brand new console called VConsole2, and a new version of the Hammer map/game editor. Curiously, VConsole2 appears to be a separate program with its own window — rather than Source 1’s in-game console. Hammer, which has gone virtually unchanged for a long, long time, has also been overhauled for Dota 2/Source 2.

How to run Dota 2 in the Source 2 engine

If you want to take Source 2 for a run, follow these instructions:

Install Dota 2 via Steam. Right click Dota 2 in your Steam Library and click “View Downloadable Content.” Put a tick in the “Dota 2 Workshop Tools DLC” checkbox. This will trigger a 5GB download. Open up Explorer and navigate to wherever Dota 2 is installed. Then navigate to SteamApps > common > dota 2 beta > dota_ugc > game > bin > win64 (pictured above). Run dota2.exe .

That’s all there is to it. Now I’m going to play around with some DLLs and see if it’s possible to run other games in the Source 2 engine.

So, where’s Half-Life 3?

By this point you’re probably wondering why Valve chose Dota 2 as the stage for Source 2’s debut, rather than Half-Life 3. Well, for a start, it’s important to note that this is definitely a soft launch. We probably won’t see a lot of fanfare or an “official” launch until there’s a new triple-A game that uses the Source 2 engine and all of its glorious new features. This first official Source 2 game might well be Half-Life 3, though I wouldn’t be surprised if it was TF3, L4D3, Portal 3, or some other game entirely.

The other possibility is that, believe it or not, producing a big, pretty Source 2 game just isn’t a priority for Valve. As Gabe Newell noted in a Reddit AMA earlier this year, “The biggest improvements [in Source 2] will be in increasing productivity of content creation.” User-generated content from the Team Fortress 2 and Dota 2 Workshops have been a massive success story for Valve, both in terms of financial rewards and user engagement. I’m sure Half-Life 3 would make a lot of money, too — but rather than sinking hundreds of developers and millions of hours into a triple-A game, it’s probably much more efficient to just make more hats.