Germany Strategy- 1944 Scenario
The 1944 scenario is, obviously, very difficult. Germany is under attack from three sides and the air, faces overwhelming enemy superiority on every front. Furthermore, there is a significant lack of modern equipment and manpower. You are under serious pressure. This scenario is the only one I have played which taught me that a unit at a third of its strength and with a tenth of its organisation can be considered "combat ready".
There are some positive aspects too, however. The first and foremost is - you are still winning the game. The Axis leads in victory points. You have also got extremely advanced technology in all fields.
This guide of survival will merely cover the basics. I will do this by theatre, but keep in mind that you have to follow all these courses of action at the same time.
Attack the D-Day landings as soon as the game begins; pull together all the forces you can from all over France and the Low Countries to do this along with some veterans from the east. Panzers mainly. You absolutely have to smash the landings, and you can win if you pull all your forces together. The Americans will quickly fan out and start capturing territory. Forget Brest and concentrate on holding Paris. Otherwise Hitler's assassination will raise dissent and kill leaders (or his failed assassination for that matter). Use available Luftwaffe units to support as long as you have fuel. Don't waste fuel on planes... yet. There is a 22-submarine unit under Dönitz' command in Germany. Use this and sail into the channel, supported by all submarines in France. This should enable you to cut off reinforcements for awhile but your subs will be destroyed. So maybe you should wait.
If you brought proper reinforcements from the east then you should be able to fight back the allies. Until then keep your panzers/mots together. Speed is crucial because the American doctrine starts to shine in later years. They recover org faster and will win battles because your men are exhausted. You have to be the defender. Try to encircle them inland. I've found that if they are "destroyed" on the beaches then they really just escaped into transports. Maybe use your subs to stop this. The Allies will come back unless you kill every division. Western France will be quite but annoying landings in the north (to Netherlands) happen a lot. Keep beach defences there.
In Italy, you can hold the front line you begin with. Gather all your forces in Italy on this front line and dig in. The Allies will make many attempts to dislodge you, but will probably fail. If you feel extremely bold, or you can manage to send additional reinforcements here, you can even try to attack. But be warned - Italy is an easy theatre to hold, and there is no direct threat from here. Any excess units (such as those enabling you to attack) will be desperately needed in the east, however.
All units in Norway and Finland ought to move to the Norwegian-Finnish border. I do not think that holding Finland is possible in the 1944 scenario. In Norway at least the units will survive and do some good by tying down a large number of Soviets.
The Eastern Front is clearly the most decisive front in this scenario, and the war will be won or lost here. The Red Army is in the middle of its summer offensive against Heeresgruppe Mitte (army group centre) and will succeed if you let them.
The first thing to do is to assume full military control of all your allies, and move all their armies (Croatian, Hungarian, Romanian, Bulgarian) to the front, especially reinforcing the southern part. You can get the south to hold by doing this, and free up German units to reinforce the centre.
The second thing to do is to move back the entire Heeresgruppe Nord (army group north), that is about the northern third of your army, from its extremely vulnerable position at Narva to south of the Düna/Daugava (that is the river south of Riga). Here you can establish a new and stable front, and save your almost only intact army group that you have left. This is invaluable, because you can use this to further reinforce the centre.
After the Preliminaries
Now your only hope is a flexible defence, and pocketing bits and pieces of the Red Army when they advance too far, while trying not to fall back too far yourself. A constant see-saw motion of the front line is probably what you will be looking at. Your IC should go into reinforcing and upgrading your units. Forget production. In fact, you can cancel just about all the production going on. Eventually you will run out of manpower, then prioritise the Panzer units and upgrade.
With the minor Axis armies tied into a coherent front line, you can achieve numerical superiority over the Soviets on a purely local level. This means that counter-attacks can be effective, and you will be able to snip off packets of ten and twenty divisions every now and then, encircle and destroy them.
This is your only hope of survival.
Eventually, after a few months of incredibly intense warfare, with losses staggeringly high, you will begin to notice a thinning of the Soviet front line, or you may tear a huge hole right in it.
Back to Blitzkrieg
This is the moment where you revert to the tried and tested methods of Blitzkrieg - you take your armoured formations and charge in the old manner, rolling up the enemy front line from the wings, encircling and destroying his units as you go along.
If you destroyed enough of the Red Army in your retreat you could assume offensive operations in 1945. Likely though it will be 2 heavy weights beating the shit outta each other though in 1945 and you'll have to wait until 1946. By then Soviet units should be being destroyed in battle or really low on strength.