Epic Games and Mozilla have revealed the first glimpse of the Unreal Engine 4 running in Firefox and the results are pretty impressive. The video you see below is of Epic’s Soul and Swing Ninja demos running in Firefox at “near-native” speeds and without plugins.

The results were made possible thanks to advancements made to asm.js, a “supercharged” subset of JavaScript, Mozilla said. In the past year, Mozilla has made optimizations that have increased the performance of Web applications using asm.js from 40 percent to 67 percent of native, and the company said they expect it to get even faster.

“This technology has reached a point where games users can jump into via a Web link are now almost indistinguishable from ones they might have had to wait to download and install,” Mozilla CTO and SVP of engineering Brendan Eich said in a statement on Mozilla’s website. “Using Emscripten to cross-compile C and C++ into asm.js, developers can run their games at near-native speeds, so they can approach the Web as they would any other platform.”

In his own statement, Epic Games founder and CEO Tim Sweeney said the Web has a “crucial part to play” in the future of game development and deployment. “And Mozilla has proven it is the catalyst to make this happen,” he said.

Epic Games and Mozilla will show off Unreal Engine 4 running in Web browsers at the 2014 Game Developers Conference in San Francisco next week. GameSpot will be in attendance.