Sprite engines come in two varieties:

1) hardware -- APIs for accessing hardware sprite
     features of various platforms

2) software -- for sprites implemented completely
     in software accessible to any platform

* Software sprite engines offer cross-platform
  development opportunites

* Hardware sprite engines offer sprites with
  minimal impact on program speed

* There is no reason why you can't mix the two,
  using the software engine for cross-platform
  development and the hardware API to enhance
  the game on a specific platform.
