Mobs do provide some of the best fun in game, some of the best fun I ever had was chickens+mods in MC, although the minute 'zombie dogs' was mentioned for Rising World I thought of penumbra.
*shudder* You are going to want a seriously sharp pickaxe.
Really loving first impressions of the game, and you seem to be dedicated with frequent updates unlike some other voxels. Can't wait for the 'planned' implementation of gravity affected water.