I played both games, 780 matches in codMwM and around 200 in codWaW, and infinite tactics developed by me, no, i am not going to tell you but you can find some useful information in the texts bellow, very few compared to my hard worked complete tactical book i am revealing this since i will be moving almost completely to black ops and goldenEye (but i am not going to stop completely with WaW and MwM) have a fun, i am pretty sure this will help you with Black Ops/golden Eye too.
Don't cheat, don't use action replay online, don't glitch
WaW:
weapons: recoil gives it more reality and makes the gameplay and multiplayer harder, scopes are annoying if used to instant kill from close (what annoys me the most), also you can glitch some weapons by pressing the 2 triggers what annoys me a lot because its a off-game way to cheat around -.- since the developers made them without supposing you can fast as you can press the triggers or even use 2 triggers, what makes those weapons the best and other weapons totally dispensable (apart the scopes), little mistakes by the developers
grenades: are almost useless tough, you throw and even if its a very perfect thrown it wont kill anything, and you have to finish with a few shots, what can end up with your death since switching takes a little precious time
bottom screen: the map doesnt show the foe's location like MwM what makes it harder and more intense than MwM, you can sneak in your enemy and you must be looking everywhere when walking, the only con is that in some closed maps like factory and in a 1 vs 1 match or 2 vs 1, it looks more like a hide'n'seek game than a fps, and eventually on a 2 vs 1 match depending of the map the alone player has advantage
aim: it doesn't show if you hit your enemy when shooting like MwM, part of the gameplay, it makes it harder
MwM:
weapons: there is no recoil, maybe because the new weapons recoil is dispensable, since they have a improved technology, there is no 2 trigger glitch because there is no "fire as fast as your fingers can" weapon, the pistol...yes..but its almost useless, and the insurgency shotgun..yes but it is totally useless too, there are no scopes.
grenades: very useful, instant kills if it hits
bottom screen: the map actually shows your where your enemy are what changes the gameplay completely, tough it is possible to trick your enemy with this, and there are some ways to be "stealth" on it, what you cant do is sneak in your enemy lines in a open field hiding in objects quickly, but generally its a question of experience
aim: it actually shows if you hit your enemy, makes it easier to know who is hitting more, and with experience you can calculate the damage of your bullets and know exactly how many body/head-shots you kill a person with that weapon, makes it easier to save some clips
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Quick Personal notes:
lol, complete gameplay review, sorry about my english, i am from Brazil and i am 15, i am not used to use translation tools, i prefer writing everything by my own even if its wrong, thanks for taking this in consideration.
Don't cheat, don't use action replay online, don't glitch