This example shows the power of zombies in Margo.
Consider the following position, with Black to play. Black outnumbers White 20 to 14, but both black groups are vulnerable to capture at a. Can Black save the game?
Blocking White's attack by playing directly at a does not work, as Black's combined group is then vulnerable to a devastating capture at c.
Alternatively, playing at b would let Black threaten a connection between their two groups next turn (left), but this would still leave them vulnerable to White's killer reply a (right).
The correct move is c. This protects Black's groups from capture and puts Black in a winning position.
This result may not be immediately obvious, but consider what happens if White attempts to now play at a. Most black pieces would indeed be captured (below), but the black zombies surrounding a mean that the white piece would have no freedom after the move, hence this would be an illegal suicide move. White cannot make this move and the black groups are safe.
So groups with a single eye can be safe in Margo if zombies protect that eye. This demonstrates the power of zombies and a major difference between Margo and Go.
This example is based on a position from an actual game (Margo game 299 played between camb and rdreilly on the gamerz.net server in 2011/12). The following example shows the same principle more clearly on the 4x4 Spargo board, in which Black has a single group with a single eye that is safely protected by zombies.
Who will win this game? Counterintuitively, the next player to move loses, regardless of colour! This example demonstrates how difficult Margo can be to analyse, even in the end game, even on the small 4x4 board.