What is MvM? Is it a Hero Defence / Tower Defence? Live TF2's "Mann vs. Machine" game mode is similar to RTSs' Hero Defense custom maps, as player controlled units are the ones fighting waves of enemies, bounties go to upgrading those units DPS, survivability and other attributes, there are of course differences as the RTS and FPS genres' versions of Hero Defence play differently, as one has units automatically attacking anything in their predetermined range at a constant DPS and hit/miss/criticals are affected by an unit's attributes and are determined by RNG, while in TF2 it's all based on a player's accuracy, positioning, weapon used, ammo and connection quality. Another feature of TF2's MvM is that a single unit will lose you the round/game should it reach it's destination, should you kill it, another one will take it's place. In a RTS's HD map the lose condition is triggered after a number of regular enemies (or a single boss every X waves) gets past your forces. Warcraft 3's "Enfo's Team Survival" is an example of a Hero Defense map. Tower Defence custom maps have players deciding the placement and type of static auto-attacking units, replacing the need for constant input seen in HD maps (to position themselves, target the most dangerous enemy in a wave, to dodge attacks or kite enemies) for long-term planning, as saving money for the upgrades while losing a few hitpoints is a viable playstyle. The enemy's danger is no longer based on their damage output, but survivability and their support abilities. There's ton of examples in old Warcraft 3 custom maps and you'll be able to find a few modern Dota 2 maps Green TD Reborn Should you decide to port MvM into TF2C, you'll want to consider the strenghts and weaknesses of both type of games. Conclusion FPS MvM (A hero defense) rewards an individual player's skill while requiring their constant input, players can and will die leading to penalties such as losing resources, waiting to respawn or losing the game. As a FPS, network quality (distance to server) is a factor as attacking enemies you see 300ms later than anyone else is a huge disadvantage, even with lag compensation. RTS's TD have players planning ahead, tweaking their army composition to match the enemy or finding success after following the actions of other players. High ping isn't as bad as slower reaction times will not hinder a player controlled unit's DPS (but lagging players will place/upgrade units later than anyone else). Why/How A MvM rework into the TD style will feel awkward as everyone's used to the Hero Defence playstyle (MvM started on August 15th, 2012). The tower models can be created from existing assets, resized/recolored mercenaries to represent different unit types and their strenght values/attributes. A Tower Defence based MvM is worth looking into instead of just copying TF2's MVM and removing the Pay2Play features/6 player cap/RED only.