Wether the action game be a high action RTS like company of heroes or World in conflict, a shooter like Gears of War or an action RPG like The world ends with you or Crisis Core FF7. The most important thing to have in an action game is to have a great flow in the combat and gameplay. It's not the shiny effects or big graphics or high production value, If an action game is ever too slow and boring it defeats the purpose of the game being an action game, but then again if things are just going on everywhere and your sences are going crazy at all the explosions and input you are doing that is bad too. These sort of games need a great flow, gears of war quick cover snatching or World in conflict recharging Special powers system are great examples, they're not difficult, not overwhelming, are good fun and keep the game flowing well. In something like TWEWY a system is incorporated where if you only battle with one of your two characters, you wont get bonuses from a thing called a light puck, which, when you battle in tandem well, increases damage output, These things all make combat flow really well, feel intuitive and fun and dont get stale. Take an example of some bad action gameplay mechanics: Frontlines-Fuel of War isn't a terrible game, but its drone battles just break up gameplay and feel choppy and gimmicky, and having to duck all the time to aim well slows you down and makes everything monotinous. All this taken into account I put foward that without great combat/movement/set piece/cinematic flow,an action game can only ever be mediocre.
