Pay-what-you want fighting game engine EF-12 and fast-paced action game Mitsurugi Kamui Hikae were both greenlit on Steam this past Wednesday, though Steam release dates haven't been announced. Mitsurugi Kamui Hikae made it to the top 10 in ten days, but EF-12's greenlit status comes with interesting prospects for both modders and other players.

We talked a bit about EF-12 during Tokyo Game Show. It's a fully moddable fighting game engine along the lines of M.U.G.E.N., with everything from arenas, models, and moves to even the AI being designed for easy modification. The game's documentation, which has all the information about how to mod the game, wasn't available in English at the time. It is now, and you can get it from Playism.

The easily moddable nature of EF-12 makes it look like a great match for Steam Workshop. Steamworks is the system behind the Steam overlay, achievements, and other common Steam game features, but it also includes the Steam Workshop, which if incorporated into a game allows modders to easily distribute content for that game. Steam Workshop is already heavily used this way for games such as Team Fortress 2 and Civilization V, making it easy for regular players to find and install great user-created content for their games directly through Steam. Once EF-12 has been modified to work with Steam Works, it should be very easy for users to share their mods with other users.

Since Valve doesn't allow developers full access to the Steamworks system until their games have been approved for Steam distribution, it's still too early to say how, exactly, the process of modding EF-12 will change. Playism representative Nayan Ramachandran did answer a few questions on the matter for us, though it's worth repeating that it really is too early for solid details.

Right now EF-12 is set up so you can drop your models and stuff into the assets folder and go. Will that change with Steamworks? Will people be required to go through the Steam Workshop system to modify a Steam copy of EF-12?

While nothing is finalized, I don't think [Masahiro Onoguchi, the lead developer,] would want the Steamworks version of the game to be such a closed system. The best case scenario would be having the option of either dropping characters into the appropriate folders, or letting Steamworks do the heavy lifting for you. Again, Onoguchi is still in the early stages of learning how Steamworks implementation works, so none of this is set in stone.

How is Steamworks going to handle modding AI? Will Steamworks be able to modify the spreadsheets directly or will something have to change?

It's hard to say at the moment. Once Onoguchi gets a better handle of what Workshop integration is capable of, we'll be able to talk about the logistics of this.

Are there any other potentially big changes in how to mod the game that will come from this?

I think the biggest changes will be in how the community forms. Hopefully we see creators seeing each other's EF-12 creations, and be inspired to one-up those creations. There will also be a big change for the casual user as well. Instead of having to roam the web looking for a cool character, they'll have a plethora of options right in front of them in the form of Workshop.

Is there a possibility that modifying Steam and non-Steam EF-12 diverge into two different things altogether?

I think it's too early to be able to make a judgment on this.

In general, it seems like modifying EF-12 to fully integrate Steamworks is going to be a pretty big task. Do you have a projected ETA to completion?

Not at the moment. Our hope is to get it into Steam users' hands as soon as possible without compromising quality, but we don't make a habit of announcing release dates for titles unless we're 100% sure it will be available that day.