One of the nicest features is that whenever you observe an effect that unambiguously tells you what a potion/scroll does - such as throwing a potion - that type of object is automatically identified for you. In more "traditional" hack games you'd have to write notes yourself even though obviously a thrown potion exploding into fire means it's a potion of liquid fire, right?
Shattered Pixel is a good way to kill some time on public transit or similar.