Back compat on Xbox - the Numbers:
Total Number of BC Titles
538 Xbox 360 Titles
2103 Xbox 360 Titles Total (25.58%)
1900 Xbox 360 Titles Total Excluding Kinect and Peripheral Based Games (28.32%)
33 Original Xbox Titles
1047 Original Xbox Titles Total (3.15%)
The current tally of Backwards Compatible titles on Xbox One stands at 571 titles, 538 Xbox 360 and 33 Original Xbox. According to Wikipedia 2103 games have been released on Xbox 360, so that makes about 25.6% of the total library available on Xbox One. Since all accessories and peripherals from Xbox 360 era do not work on Xbox One, its fair to exclude these titles from the total list. This includes all Kinect Titles, Rock Band, Guitar Hero, uDraw, Tony Hawk, DJ Hero, Scene it, Lips etc. This brings the total number to roughly 1900 titles. This brings the total percentage of BC titles to about 28.3%, not bad.
Original Xbox is of course totally different. Licensing is way more complicated and making games work properly in the emulator is presumably more difficult as well. 33 Original Xbox Titles have been released since its inception in October 2017, a total of 3.15% of the total 1047 games released on Xbox.
Retail vs Xbox Live Arcade
Xbox 360 launched the concept of Xbox Live Arcade games, smaller, cheaper and generally more simpler games. These took off once some of the games became really popular like Shadow Complex, Mark of the Ninja, Peggle, Limbo etc. In the end XBLA games formed a good part of the Xbox 360 library and there has been some debate whether or not Microsoft prioritised XBLA games over retail games for BC, because these would obviously take less time and work to bring over because of the complexity of the games. I've gathered some numbers to determine if this is true or not.
538 Xbox 360 Backwards Compatible Games
294 Xbox Live Arcade Games (54.65%)
244 Retail Games (45.35%)
Based on these numbers you could say there is a slightly higher focus towards XBLA games, especially so in the earlier years of BC. In 2018 for instance, there have only been 11 XBLA games added compared to 94 retail games. Lets take a look at a breakdown for each year:
2015 = 121 games released
33 Retail (27.27%)
88 XBLA (72.73%)
2016 = 188 games released
63 Retail (33.51%)
125 XBLA games (66.49%)
2017 = 149 games released
67 Retail (44.97%)
82 XBLA (55.03%)
2018 = 105 games released
94 Retail (89.52%)
11 XBLA (10.48%)
2019 = 8 games released (Up until January 27)
7 Retail (87.5%)
1 XBLA (12.5%)
As you can see there is a rather interesting development to be seen. There has ben a major shift to retail games this year, whereas XBLA games were the major focus point in the first two years of BC especially. Each year the percentage of retail games compared to XBLA games has gone up. But how does it stack up to the total library?
2103 Xbox 360 games released
794 XBLA released (37.0% is BC)
1309 Retail released (18.64% is BC)
Roughly 37% of the total XBLA library is now playable through BC, considerably higher compared to the 18.6% of retail library. This is off course due in part by the many sports titles and peripheral based games like Guitar Hero, Rock Band, DDR, Sing It etc which can not be released on BC. If you exclude these titles the percentage is likely to increase to around 20%, still lagging far behind XBLA. So what is the conclusion than? In the earlier years of BC the XBLA games were definitely prioritised over retail games, probably because these were easier to port compared to the more complex retail games. In the following years and especially this year the shift has turned towards retail games, likely due to the fact the emulator is finetuned and can now process most retail titles allowing for more retail games to be added.
Backwards compatibility is my favorite feature on Xbox One so I had to share this analysis of the feature on a forum with you guys. There is an even bigger breakdown of the statistical data on BC on the link I provided.
https://www.resetera.com/threads/analyzing-xbox-one-backwards-compatibility-a-numbers-breakdown-last-update-january-27th-2019.66804/