Total Mayhem takes Total Annihilation, bugfixes and extends it the way Cavedog might have. Early game pace is quicker, many new units added (longtime players may recognise some 3rd-party units), including a whole new 3rd tech level tier. Existing and added units have been bugfixed, rebalanced, re-modeled, re-textured and re-rendered to equal or exceed the standard of the original TA units.
A third barrel on its long range artillery plus some other fine-tuning of this fantastic model. Again, this suits the adjusted role of being mainly an artillery piece... albeit one that can defend itself highly effectively. Wunderwaffe. Guns.