Each turn represented twelve hours, with ground and air combat taking place only during daytime turns. Grigsby expanded the game from Guadalcanal Campaign with many new features, such as transport aircraft, torpedo boats, and the ability to use paratroops once per game. Most important of all was the ability of aircraft to support ground troops in combat. As in the previous game, an AI "player" was available for one side only, but this time it was the Allies. The Axis had to have a human player. Also in contrast, there were only three scenarios instead of six, and the "long" campaign game ran less than three months. Both sides faced the problem of how to keep their forces supplied, primarily with ship convoys, and how best to disrupt the other side's convoys. Where to base the fighters and bombers, which had been obvious in Guadalcanal Campaign, was now a challenge. Control of the air over Africa had to be traded off with the air battles over Malta.
Reception
The game's greatest weakness was the scoring system, which strongly favored the British. While Malta and Tobruk were worth 500 points each if the Allies held them, the Axis received only 200 points each for capturing them. The only high-value target for the Axis was capturing Alexandria itself. This meant the Axis had to win decisively or not at all. Another problem was the limited types of aircraft available. Historically, the Mediterranean Theatre had a wide mix of German, Italian, British, and American bombers and fighters. Grigsby's system accommodated only one fighter type for each side, and only a few bomber types. A 1983 review in Computer Gaming World complained about this lack of detail, which may have contributed to Bomb Alley selling less well than Guadalcanal Campaign. A 1993 survey in the magazine of wargames gave the game one-plus stars out of five. There were some bugs in the source code, but they did not interfere with the playability of the game. A line of code accidentally carried over from Guadalcanal Campaign halved the accuracy of the British torpedo bombers from what the manual said. However, they were still able to inflict serious losses on Axis ships. Another bug prevented the major Allied base at Gibraltar from receiving additional supplies, but there was a stockpile at the start large enough to last through most games.
