Freelance mode has 3 possible objectives you can complete for every map, whereas the story campaign is more like distinct level puzzles you have to figure out how to beat with the different combinations we give you. Bigger isn't always better.
The rational is twofold. First, we wanted to build a game that tailors itself to the desired experience of the player. To say I'm a huuuuuge fan of JE Sawyer's work would be an understatement; far as I'm concerned, he and Jaime Griesemer are two of the most interesting designers working in game right now. I didn't have the pleasure of attending this talk on person but it exemplifies my own philosophy with game design, which is that the onus on the designer is to provide the player with as wide a range of viable builds as possible without them all actually being optimal. Here's a link to the talk, I highly recommend it if you've played Pillars or if you have any interest in game design:
http://www.gdcvault.com/play/1023481/Gods-and-Dumps-Attribute-Tuning
What we did with Brigador is build an enormous variety of playable vehicles and weapons. For "optimal" builds there's probably only a small handful, but I don't care about optimal. We built the variety for role-play and for difficulty management. In our game not all weapons and vehicles are created equal. But they're all different, and they all have their own flavor text. The idea is that if you actually invest in the game we give the option of pretty much any playstyle you want within the context of the game at hand. Want to be a giant tower of destruction with a huge explosive minigun and giant MIRV artillery? We've got you covered. Want to be a tiny hovercraft with a stealth suite and radiation guns that boil the pilots in their cockpits? We've got that too.
The Mech Warrior franchise is probably one of my biggest influences growing up in games, and I can't tell you how important it was to be able to not only pick the mech I wanted but load it out to my exact specifications. We don't manage the same microscopic customization per mech as MW does, but we make up for that by providing a huge variety of playable vehicles and weapons. Also there's only 4 of us making the game, so it's hard to compete with big studios in that regard.
The secondary reason is that honestly we just don't have the bandwidth to create custom content across a large spectrum of playable levels. When you have 40+ playable vehicles, it's extremely difficult to also provide a huge variety of possible end goals without reducing the player choice to insignificance. By locking the freelance objectives to a set 3 choices, yes it's not super varied, but at the same time it gives you a fixed target to shoot for, and also allowed us to actually design around having such a large number of playable vehicles be viable. As a player you can go ultra-violence and kill everyone / everything. This is the obvious choice, and the easiest to design for as well. The other two choices are assassination and objective destruction. With the former, we have to provide the player with the ability to get in and out quickly, also to enfranchise positioning. To that end we have directional damage (rear hits deal 2x-3x damage depending on the target) and a variety of weapons that can be applied at various ranges. The Black Hand for example is a current favorite, as while it's useless against shielded targets and deals no damage to the environment, it has enormous environment penetration and is very quiet. Since targets do not raise their shields unless alarms go up, this allows you to assassinate targets through obstacles without alerting nearby targets, while using an active camo ability to navigate the playable areas without detection.
We've done our best to give you a field of play that's worth exploring. The objectives themselves aren't "deep", but then again very few games are in that regard. In Spelunky your only goal is to get to the next exit. Nuclear Throne and Binding of Isaac it's kill all the units in your way. In that context we actually give you far more choice in the matter, and because we frontload all the customization even though not a whole lot changes *during* combat, we give you way more choice in how you play the game.
I hope that clears things up a bit. Let me know if you're got any other questions!
