These two Microsoft announcements should have Sony very worried

Microsoft just wrapped its big press conference at E3 on Monday, and it was pretty dang impressive.

The company announced support for Xbox 360 games via backwards compatibility, support for virtual reality headsets from Oculus and Valve, support for Microsoft's own holographic headset, a new "elite" controller, a bunch of great-looking first-party titles and a slew of creative new indie games, too.

But from all this news, two of these announcements should have Sony worried.

Backwards compatibility: 100 games is better than zero

Microsoft announced the Xbox One console will be able to play your old Xbox 360 games: If you have a disc, you can put it in the slot, or you can get a digital copy for free.

That said, this isn't for all Xbox 360 games - Microsoft will launch this service with just 100 titles at first - but those titles include "Mass Effect," arguably one of the best games from last-generation consoles.

Still, backwards compatibility with 100 games is still better than Sony's PlayStation Now service, which is not only limited to certain PlayStation 3 games but also rather costly. You can rent and play old PlayStation 3 games for what comes out to be around $15 per month - but it doesn't matter if you already own the game, you still have to pay.

"We won't charge you for the games you already own," said Xbox chief Phil Spencer.

The virtual reality wars: 2 vs. 1

After Facebook-owned Oculus VR announced Xbox One and Windows 10 support for its virtual reality headset late last week, Microsoft on Monday announced it's partnered with Valve, which is working with HTC on the Vive virtual reality headset, to make that hardware compatible with Xbox One and Windows 10 as well.

In other words, both Valve's and Facebook's virtual reality headsets - which people are absolutely gaga over, by the way - will work on Windows 10 and Xbox One. Sony's PlayStation 4 console, on the other hand, is only known to be compatible with the company's own Project Morpheus headgear.

So, while Sony may offer a more integrated virtual reality experience through Project Morpheus on the PS4, at least Microsoft has two incredibly popular virtual reality headsets to work with. Oculus is the biggest name in VR, having launched excitement for this space with its immensely successful Kickstarter campaign three years ago, and Valve, which makes really popular games like "Half Life," also runs the Steam store, which is the world's biggest store for the distribution of PC games online. That ought to give Microsoft a huge leg up in terms of virtual reality content, at least at launch.

Sony's press conference begins at 9 p.m. ET Monday.