M&M Field Battle Rules
The normal M&M Minion rules are great: they reflect the genre and speed up combat. But you are still left dealing with each opponent individually, which can make large battles slow and boring (particularly since the individual minions are not a real threat to most heroes, so there's less sense of danger).
The Field Battle Rules from the back of Golden Age take mass combat a step farther. The concept is similar to the Swarm rules from D&D, in that you take multiple creatures and consider them a single unit for combat purposes, except here you use the base stats for a single creature and apply a “Force bonus” to most checks based on the size of the group. The concept is simple, and it makes a great extension of the M&M Minion rules for any setting, not just WWII.
There are a few pitfalls in the rules as written, so here are some tips for using the Field Battle Rules effectively:
1) Don't mix different size units. If one side is smaller, break up the other side into matching units (so run four platoons vs one platoon instead of one company vs one platoon). Otherwise the increased bonus for combining units is not as good as just making multiple attacks and having separate damage tracks. Combining four platoons into one company changes the Force bonus from +5 to +6, but now you are only getting one attack, and one hit can take out the whole group. Four groups of 50 will always win vs one group of 200, despite being the same number of men.
2) Try to break the force into enough units that each hero can be attacked once per round (assuming you are pitting units vs heroes not units vs units). So if there are four heroes, break a company down into four platoons. Otherwise you get the odd case that the entire force only attacks one hero at a time.
3) Treat all powers as Damage ranks instead of having non-damaging powers do nothing (so Mind Control 10 requires the same save as a Blast 10). This lets heroes do creative things with their powers and it keeps things moving fast. Mind controlling an officer to sow confusion or blinding the troops with a sandstorm does just as good a job of disrupting units as punching or blasting people.
4) Use in-between sizes. The Force modifier is based on the progression table, but the real world military unit examples jump from +6 to +9 because there are no units that match the sizes between, but that doesn't mean you couldn't have a unit at the +7 (250 creature) size.
Used properly you can run large battles with your heroes taking on hordes of agents, giant rats, Atomic Supermen, whatever. And what superhero doesn't want to fight off an army of invading aliens, so long as they don't have to roll a million attacks to hit each and every one?
Because they are in the back of Golden Age instead of one of the core rulebooks, it seems like few M&M GMs have even heard of the Field Battle Rules. I'm guessing most GMs are unwilling to buy a whole book just to get a few pages of mass combat rules if they aren't interested in the rest of the setting. If we're lucky Green Ronin will release them as a stand-alone PDF product for a smaller price, because they are a good tool that more GMs could benefit from.