For those of us still playing 'the game'...
Maiden have been adding the number '17' to some of their album covers
Chalk marks on the front of the tank...
...underneath the skull and crossbones (for an extra point, the key that Eddie is holding is the Chinese symbol for death)...
...and it's hard to spot, it is possible to make out XVII (number 17) in the scratches on Eddie's body. There also appears to be an XVII and the Chinese symbol for death in Eddie's eyes