Grinding

I have been playing everyday I'm lv 51 and even though I have not yet unlocked all units I'm doing pretty well.my only problem is it won't let me fight in all the arenas so I'm stuck in Europe Killin lvs 15 which is unfair on them but in a way good for me for medals and green cards. For new players if u want to level up early on I recommend Europe mission 4 and Africa mission 1 these two are pretty easy missions I recommend using auto as the lv 4 mission u have allies who attack from the west so they actually get to the enemy base first. Don't rush other missions too quick use radar regards examination of your enemy allows you to plan ahead. Invest in the mammoth as it has double shots. Level it up early on it will help u later especially in south America. Different units effect different enemies I.e a.p anti personal a.t anti tank a.a anti aircraft and anti turrets.u get my point this game takes alot of patience as each mission requires different strategy one could be land based another ocean based air forces are brilliant to have they allow you to target enemy turrets far away from your land and naval units. The more airports you capture the more air units u can buy.if u keep resource cards ranging from 100 to 350 use them to buy more air units. Be Warned some units have anti air guns that will do damage to your air craft. It is paramount that u always protect your airbase by leaving a unit on them they are a prime target to enemy forces. Oil too is important u don't want to be in battle with no fuel. Challenges are great for getting items and cash. They are not player controlled so don't worry or panic thinking the games crashed or its a fault no its a.i based computer vs computer so sit back have a coffee and enjoy the show. I tend to recommend definitely to keep cards such as radar medic and credits at the first two maps I.e European and Africa. Oil and building repairs I tend to sell as I always have units protecting my base and paratroopers on oil fields.