Publishing Your Game to the Windows 8 Store - Releasing HTML5 Games for Windows 8 - page 89

Second, you should leave “Include app names that already have packages” unchecked. This
is used for submitting an update to an existing app. We will discuss submitting updates in the
next section.
Next, you will need to set up the version number and platforms you want to release your
game on ( Figure 6-7 ).
Figure 6-7. Set up the version number and platforms your game will run on.
As you can see, you can choose x86, x64, and ARM as the desired platform architecture, or
Neutral for all of them. If you are building an HTML5 game there shouldn't be any issues
having it run on all platform architectures, outside of performance differences.