Good point, I'll seperate DXEngine into the following static classes:

DirectXGraphics
DirectInput
DirectSound
DirectMusic
DirectShow
DirectPlay (network stuff)

(The names may change.)

The TileEngine and SpriteEngine classes will manage the Tile, Tileset, and Sprite classes. Again, these may be renamed for clarity.

This is good. I'm thinking the ParticleManager class will handle things like creating and releasing Particles and ParticleSystems, while the ParticleSystem will handle positioning and drawing Particles. Particles are simple data structures with position, velocity, color, and maybe sprite information.

I'm wanting to handle character movement a bit differently than this. Because essentially any object will be playable, I would like to implement dynamic input mapping for all objects. In other words, when a game begins, the left and right arrow keys will move your character object left and right, but in the middle of the game, these keys can be reassigned to move a stationary missile turret. This way, it will be easy to switch control between characters, vehicals, guided weapons, etc., and allow multiple players on a single input device.

Any information you have on network code would be great. I know nothing.

-Nag