You don't. 10+ maps, 1 guy can make a map in about 3-4 days. Make it a very detailed map, take around 5 days then. Phyisics and AI should be in their game engine already and should only take tweaking. Gameplay for single player, I guess that's about 2-3 storylines? Wouldn't even want to start counting the ones RS has. Achievements? Simply for all games, lamest thing ever. Really, I don't need to know someone bought that, or killed that guy or had that many kills with that weapon. Not even hard to implement, just increase a global variable. Weapon balance: Compare the amount of weapons of COD with the amount of RS. And I agree, some of RS weapons aren't balanced too. But so has almost every game. Theatre mode: It's just the high poly versions of the models, and some tweaks here and there. Soundboard: Over 750 different songs, with a lot of dynamic area sounds, and sounds effects like eating, hitting,... Making the sound for a gun is as hard as making the voice for a boss. Record it, edit it, implement it. Ingame statistics are just reading the right variables. RS has 10 year of regular content updates. That said, every game is different and is hard or almost even impossible to compare. Some games rather go for graphics, others for gameplay. COD is and stays a shooter. Oh and I read the other posts: COD Black Ops still uses the IW Engine. As did the previous COD versions. And I didn't count in the time it takes to model the graphics.