Considering past trends, Mass Effect's co-op horde multiplayer mode ought to be rubbish. Big studios went through a phase of tacking vestigial multiplayer modes onto their big singleplayer games, to encourage long-term engagement and sell some loot boxes. These modes were crap because they were transparently produced to meet business aims rather than enrich the fantasy of the core game.
Frequently they were produced by different studios. Digital Extremes, creators of Unreal Tournament, The Darkness 2 and now Warframe, had the unenviable task of creating an arena shooter multiplayer mode for Bioshock 2. It could have been the best multiplayer mode ever created, but the offering was too bizarre for Bioshock fans. 2K served us a steak dinner with a milkshake on the side. Ubisoft never quite nailed the idea of a hide-and-seek Assassin's Creed multiplayer mode, and Dragon Age: Inquisition's co-op mode was entirely forgettable.
Mass Effect gets it right, first by coming up with a thematically appropriate reason to shoot lots of enemies with friends. You're a special forces unit hunting down resources, stealing intel and hacking archives while under fire from one of the three enemy factions. While objectives like 'squat next to three terminals to hack them' seem arbitrary, the opportunity to occupy new roles in the Mass Effect universe outshine the contrivances of a multiplayer combat arena. You've met an Asari huntress in the main game, now you get to be one.
Mass Effect 3 in particular did a great job of letting you inhabit characters that receive brief mentions in the main game. The mode's best character arrived some time after launch, when an update finally let us play as the tiny, rotund Volus. While Asari teleported around the map, unleashing psychic powers and headshotting outlaws, the sheepish merchant Volus gamboled clumsily between cover points, occasionally pausing to blast an enemy with a shotgun as big as him. Such a character might have been too silly to feature in the main story, but in multiplayer you can broaden the universe and have fun without totally undermining the fiction. At least, that's what I told myself as this weekend I watched a Krogan batter a huge mech to death by headbutting it repeatedly in the knee.
This 'loosening up' effect applies to Mass Effect's combat and progression systems too. The multiplayer mode doesn't need a laborious crafting system. It doesn't have to gradually drop new weapons and powers into your toolset over 60 hours. Instead I can open a loot box and suddenly play with an assault rifle that fires grenades. The core RPG, thanks to its sheer size, can't deliver those surprises with the regularity of a multiplayer mode.
Putting the bloated research and crafting system aside, Mass Effect: Andromeda does a good job of tackling the challenges of creating long-distance progression in the context of a high-mobility third person shooter combat system. Ten years ago action games only had to provide enough new tricks to keep you entertained for ten hours. As genres have merged, similar systems now have to support 60-100 hour RPGs. Old fashioned class systems that silo some abilities and lock of the rest are a necessary casualty—Andromeda is right to give you the opportunity to switch between roles at will.
Even here multiplayer enhances the core game with a varied stable of unlockable soldiers. In singleplayer your powers can interact with six other power sets—those of your companions. In multiplayer there are dozens of power sets and a huge amount of crossover potential. Using a psychic lance to explode a frozen enemy feels great, especially when your friend has done the freezing.
To its credit Andromeda's combat systems support these co-operative high-five moments well. Let's not underestimate the value of looking cool in front of your friends. Andromeda's animations, as you flip over cover and dash in mid-air, are all about showing off. It looks great. In all these ways Mass Effect multiplayer teases secret extra entertainment out of a system fundamentally designed for one player. It's bonus fun.
I even like the unlocks system. You can put money into it, but I've never felt pressured to spend, and I enjoy the choice of whether to get a small box or save for the big caches full of exotic weapons and new characters. So far it's been generous with its points, and the characters level at an exciting pace. Overall, it's a sensible evolution of the work started in Mass Effect 3. To think, I almost dismissed it out of hand. I would never have witnessed the might of the roly-poly Volus Adept, or the extraordinary forehead power of a determined Krogan.