I really love Scenario 1 from Stalingrad Pocket II.

It seems like the Red Army has to annihilate the Romanian line with little work, but the Soviet player has to play very precisely if he wants to grab the objective cities in time. If the Red Army player, confident about his superiority, attacks everywhere, he surely will push the Axis line some hexes every turn, but he will never break the line definitely, as reinforcements and reserves will act as firemen blocking all the breaches. So, I think the Soviet player needs to concentrate his main armored forces in a schwerpunkt while threatening alternate moves in other spots to pin Romanian units badly needed to defend against the main offensive.

I have tried this offensive successfully:

The Red Army launches a strong offensive between Korotkovskii and Blinoff. Relatively strong forces attack, with artillery support, near Kletskaia, thus threatening to open the road to Kalach and Nizhne-Chirskaya via Osikinskii and Golubinskii. 4th Rum Corps needs to get that road blocked, or the Axis lose the game, so few units can be diverted to Perelazovskii. The Axis line will be severely battered between Blinoff and Korotkovski, so Axis armored reserves are committed to reinforce the line. (An expert player will maintain a reserve, but a lot of players will run in panic to the front.) The Axis player always can divert units from 1st and 2nd Corps, but they're slow infantry and he still must take care of Bokovskaya. Just when the Axis thinks that the worst has passed, his nightmare arrives:

I usually do not use all my Katyushas in turn 1 as a lot of players do. My artillery unleashes a strong barrage against the Axis line in turn 2, while some armor and motorized forces have been kept in reserve for the exploitation phase. First-line forces attack the Germans in a very narrow front (2 or 3 hexes) which is usually DG'd (and sometimes has lost a few steps due to Soviet rockets), totally sinking the line. The way to Perelazovskii is now guarded by weak forces (arty, HQ's, and a few retreated units, if any).

Soviet reserves will sweep these remaining troops and take Perelazovskii, unless a prudent Axis player has the city itself occupied by any unit. Meanwhile, of course, 21st Army continues pressing near Kletskaia, so 4th and 5th Corps cannot run wildly to the rear to help block the main thrust. If the German player has not been careful, even reserve cavalry units can take Bokovskaya as soon as turn 2(!) via Malachov (11.10) secondary road, thus leaving two almost-intact infantry corps in a very dangerous position. Now panic dictates Axis moves, so I cannot go on explaining my Soviet strategies, as every game has been different from this point.

Of course, the German player wins nothing fortifying his remaining units into the cities, as the Soviet only needs to cut them off from supply them, it not being necessary to take them. I cannot speak about German strategies to counter my offensive. Every time I've played the Axis, I've found that kind of poor opponent who thinks, "I'm superior everywhere, so I'll attack everywhere." I never lost an objective city as a German player in Scenario 1. Nevertheless, I'm not very proud of this. It's not my skill, but my opponents' lack of it. They always annihilate my 5th Rum Corps -- they're very proud of it, and where do they arrive doing this? They take Verkhne-Cherenskii (15.16), a great victory for them.

I like this scenario because it's full of action, and timing is absolutely pressing for both players. If the Soviets do not breach the line quickly, they'll have a very hard time arriving at their objectives in time (if you haven't taken Bokovskaya before German infantry arrives, you can completely forget this city, so you have only four possible objectives left). The Soviet player has to find the balance between front line and reserve units allocation. Too strong front line will give a weak exploitation phase, so the Axis will have time to rebuild a line. Too strong reserves will leave a weak combat phase, so the line will not be broken and the reserves will be used to overrun the line instead of running on the enemy's rear area; again the Axis has bought one more turn, and the Soviet have very few of them to sell.

As the Axis player you have to make very hard decisions and sacrifice a lot of units to slow the Soviets down before important reinforcements arrive. Use of Axis artillery is critical, and you must keep a reserve, however little it is, every time you can. Reserve use can be the key to avoiding the establishment of a mortal game-winning breach.

By the way, I've never played this scenario by e-mail, so I have always enjoyed seeing the desperation on my opponent's face.