The game is annihilation, spear head with a twist.

The board is surrounded (as in it’s a box canyon) so there is no escape, but as well as that there is also and earthquake which is collapsing into the field and buildings.

The way this is determined is, at the start of a turn for the board and the buildings I dice will be rolled (measured from the base of the buildings and side of board).

1- nothing happens
2-3 - all models in 2 D6 should move as in difficult terrain (to represent the stumbling around as the earth trembles) and vehicles aren't effected
4-5 - a strength 5 hit, distance in 2 D6
6 - a strength 10 hit, distance in 3 D6, all units and vehicles can be shaken (on a 4+ a unit or vehicles is shaken, for units this means that they cant shoot because of being shaken around to much to get a good enough aim.

Other rules:
all units must be on the board/no reserves, unless they deep strike.
If a unit fails a leadership test and has to run away, then they must instantly die since there is no escape.
If a building collapse on a 6 then it is removed from the table, and the area is turned into difficult terrain/ the board dose not count.
All other 40k rules apply.

me and my mate will have a go at this soon
please leave a comment, any suggestions and thanks for reading