Battle of the Bulge is a turn-based wargame simulating a World War II battle at the Ardennes from December 16, 1944 and January 25, 1945 (the game does not cover the German counter-offensive and ends on December 28, though). The player takes control over either side and tries to lead it to victory.
In established wargame fashion, the map is divided into different zones (no fixed shape) and the units are represented as icons. During each turn, which randomly covers between 30 and 180 minutes, each unit can move (depending on the unit type and conditions between one and three zones) once. After movement is concluded, all active units (all which the player moved or clicked on) on a field with enemy units attack. The result is based on various variables and determines which side controls the zone.
There are no neutral zones. This is important to keep in mind because supplies play a vital role: when a unit has no path of friendly zones towards a friendly edge map at the end of the day, it is considered isolated and can't be used during the next day. The parameters of the map, e.g. the weather and replacements, are based on the real conditions; additionally the game also automatically applies bonuses/disadvantages or restrictions during specific days. For example, the Axis have a fuel shortage from December 21 forward (one randomly chosen mechanized unit is isolated each day) and the Allied can't cross the river Meuse until the Axis move towards it.
Victory depends on the accumulation of victory points. Those are rewarded for destroying enemy units; the Axis also gains them for holding certain areas at the end of the day. In turn, the Allied gain points for every isolated Axis unit at the end of December 28. The exact winning conditions change depending on the chosen scenario and current day and are checked at the end of each day (except in the Bitter End scenario). The Axis can also win when they manage to take and supply a zone west of the Meuse until December 19.
Besides the usual hot-seat mode, the game (on iOS since version 2.14) also features cross-platform play-by-mail multiplayer.