In Spellcross, a contemporary Earth military fights for survival against an extradimensional invasion of orcs, undead, harpies and other fantastical creatures.
The game only features a single-player mode, split into tactical battles and a strategic planning mode. The former is the actual combat, each unit has action points, which can be used to commit actions such as attack or move, or reserved for opportunity fire or movement. Resource and troop management, research, maps, territory acquisition and counter-attacks tie the scenarios together in a rudimentary narrative.
The newer English version differs from the older Czech version. Some graphics and animations have been improved, the mission design has been tweaked and some of them joined. The English version includes a tutorial and cheat codes. The English version has only two difficulty settings, while the Czech version has three.
Source: Wikipedia, "Spellcross", available under the CC-BY-SA License.