DBMM has many similarities with DBM which means the differences can really trip you up. Here are some of what I think are the key differences between DBM and DBMM:

Key Differences from DBM

• There are no 'zones of death' behind elements that are killed in close combat, except for certain situations, mainly Warband. This makes deep blocks of infantry a lot more resilient, even against troops that quick-kill them.
• You aren't killed just because you can't recoil any more - you just suffer a -1 in combat. However you are still killed if you lose a combat with an enemy element in front edge contact with your side edge.
• Manouver is more expensive in PIPs, especially if you wheel or manouver, especially if you are irregular.
• Regular generals now have an allocated PIP plan at the start of the battle, which speeds up regular PIP dice allocation. You have to design your commands to reflect this rather than having Swiss-army-knife commands.
• A lot of rear-support and quick-kills are now bound dependent. In general, you tend to get better rear support in the enemy bound when you are on the defensive and better quick-kills in your own bound when you are on the attack.
• Cavalry and Light Horse skirmishing with infantry is more fluid with lots of compulsory repulses.