Does anyone play this? It's free on Steam and it's like a crossbreed between TF2 and the DotA-style games.

Post your Steam ID here if you do, would love people to play with.

Ugh!

I saw the words "Monday Night" and my brain just went

FOOTBALL!!

But it wasn't true. I'm so sorry.

But tell me about this game, please. What sort of game is it? What is DotA?

DotA is Defense of the Ancients. I'm not very familiar with the genre, but my impression is that you have two bases on opposite sides of a map that put out a constant stream of army units attacking each other. Players control hero-type characters that generally aren't strong enough to march in and level the enemy base themselves, but can work to aid allied forces, sabotage enemies, assassinate other heroes, and in general work toward their side's victory.

Monday Night Combat takes a similar approach. You have an arena with two teams, which each have a "Moneyball", the general target. Each base pumps out a flow of robots that attack the other side, evenly matched on their own. Instead of a strategy-game approach like DotA, MNC is a first-person shooter, or rather over-the-shoulder shooter. You have classes like heavies, snipers, commandos, support, and so one. Each team is generally shooting at each other like in the average multiplayer FPS, but is not so much trying to rack up kills as to turn the balance for their side and take out the opposing moneyball.

MNC itself has been out a while, but this new Super Monday Night Combat seems to take the TF2 approach, being free to play but with a store filled with extras to buy.

Pretty much this. There is some strategy still in it, in how you combo skills and work together and things like that. You start at level 1 every game and can go up to 12, leveling skills as you go; three active skills and two passive skills. You pick from a group of around 6 heroes, or pros as SMNC calls them, until you unlock more. It can be fun and frustrating, just like any other game.
Free though, can't go wrong.

I don't really find it very fun. The maps are far too small. I was hoping for a game that felt like a MOBA, not a game that feels like TF2 with creeps. I wanted big maps, three lanes, items, etc.