Sacrifice is one of my favourite games ever but I will admit that the single player gameplay is not perfect. Npc opponents have poor artifical intelligence and employ the same strategy throughout the game. The game seems impossibly difficult at first but once you figure out a winning strategy you can keep using it.The game can still be challenging though because of the large resource imbalance between you and your opponents at the start of each level.
The gameplay may be flawed it doesn't matter. It is still great fun and the game oozes creativity and originality. Even by today's standards it looks and sounds beautiful. When you complete the game you are rewarded with a highly entertaining credits sequence which reeks of the loving care that the creators put in.
Sacrifice offers replayability in a clever way. There are five main paths to the end goal one offered by each of five Gods. Each God offers a sequence of nine missions leading to a common tenth "final mission". Each God has their own style and rewards the player with unique powers and creatures for taking their missions. The really clever bit is that you can mix and match missions for different Gods leading to a wide range of different paths through the game and resulting character builds. Some combinations are prohibited because a God you have fought against too often will refuse to offer you a new mission. The number of permutations is still large. Amazingly the game manages to tell a clever story which hangs together despite the random selection of paths to get to the end.