While a lot of the big announcements for E3 2017 were leaked ahead of time, one surprise didn’t slip through the cracks ahead of Microsoft’s press conference. At the event, the company announced that original Xbox backward compatibility would be making its way to Xbox One, but besides announcing Crimson Skies: High Road to Revenge for the service, further details were scarce. Head of Xbox Phil Spencer has now discussed original Xbox backward compatibility a bit more, revealing that it won’t be quite as ambitious as Xbox 360 BC.

According to Spencer, there are two main reasons why original Xbox backward compatibility won’t support as many games as Xbox 360 does. For one, there are rights issues that are more complicated than with Xbox 360 games. Secondly, it is simply more difficult to do original Xbox emulation on Xbox One, with Spencer saying that the way it is being accomplished now is through sheer horsepower.

Bringing original Xbox games to the Xbox One is apparently a challenge for the emulation team, but the horsepower of the Xbox One and the Xbox One X should make things a bit easier than emulating Xbox games on the 360 was back in the day. Plus, the added power should help original Xbox games run better on Xbox One, just as we’ve seen with 360 games.

Besides bringing backward compatibility for original Xbox games to Xbox One, Spencer has also expressed interest in doing something similar on PC. Unfortunately for PC gamers, no concrete details on that front have been shared at this time, but with Spencer’s commitment to PC gaming, perhaps an announcement will come at next year’s E3.

In the meantime, it will be interesting to see just how many original Xbox games make their way to Xbox One’s backward compatibility program. It seems likely that most of the big first-party games will come to the service, but third-party titles are less of a guarantee.

For now, the only two games confirmed for original Xbox backward compatibility are Crimson Skies: High Road to Revenge and Fuzion Frenzy. As we near the service’s launch, though, fans can expect many more games to be announced.