This north facing structure with multiple arches looks like a big stage.
The Hindu motifs on the plastered walls suggest it might not have been a Mosque. This too is a building made in the hybrid Indo-Islamic style. However this is popularly known as the Mosque.
The ruined east and west side projections are suggestive of a compound wall hem the open hall like structure of the Mosque. Being built on a high platform, a few steps in the front can take you to the top of the hall.
Visit this as part of the Royal Center tour (detailed in Route 3 of Hampi itinerary map). You'll also see a number of other attractions in the same enclosure (Dannayaka Enclosure), like the Band Tower, the Watchtower, basement of many palaces and so on. From this area you can easily head to the Royal Enclosure where you'll see a plethora of platforms and aquatic structures.
Arches of the 'The Mosque' in the Royal center area in Hampi.