I'm currently at Level 12, about to go 13 really soon.
What I found so far for me...
HEAL IS EVERYTHING: Put ALL of your points towards HEAL till it is maxed out (at 4 or 5 I think). The ability to instantly heal 40% with a pretty short recharge is priceless.
FAST, SHORT, and MORE BULLETS: Get the FAST machine gun and shotgun. They shoot fast, have more bullets, but are only good at short range. Short range is where it all happens, mostly. I can usually close the gap if I have to. Consequently, I found the fire bullets, which I ran at MAX for a while, seldom gave me any extra kills from the enemy burning out after out engagement. Dropping the fire bullets and putting my points towards HEAL instantly boosted my KDR.
GRENADES / DYNAMITE USE THESE OFTEN: Throw your grenades/dynamite around like crazy. Keep boring a path in front of you with them. Any little extra damage you can get off of these can only help you win the confrontation. On a flag I continually throw these things at every opening (or where I know the enemy will most likely come from).
6th SENSE: When you've maxed out HEAL go for 6th Sense. At first it will be short and take a while to reload, but used sparingly it will be one of the most valuable tools in your arsenal. After a while you just know where the enemy will be coming from. There's flow in these maps, and the sheep take the direct path most of the time. When coming up on a choke point you can instantly know when and where to pop that first grenade/dynamite to gain the upper hand.
LEAD YOUR TROOPS: I found that after going 22-6 or 15-1 for a few rounds the sheep begin to follow. I've taken a couple troops on the wings of my plane directly over and capped the enemies forward main many times. It's tough sometimes to get the people playing as a team, but when/if you do you can roll over the enemy it grand fashion.
I also carry max HEAL and REPAIR widgets. I end up on the winning side of most fights, alone, and having taken a lot of damage. In order to get back into the fight fully healed as fast as possible I keep these widgets handy. I only use them rarely, but they are great when I need them.
I just switched to grenades from a long run with dynamite. I only throw one (don't have multi-grenades). It works ok. The damage zone is smaller than dynamite, but it throws much better. But grenades don't stick to things like tanks either. The jury is still out on these.
Well that's my short take on this fun game so far.
I am VonHitler on the German-ish side...say hi if you see me!
