Grenades are a lot of fun in Deadzone, but the way they work in 3D is not very well explained in the Alpha. So, here I am to expand on that.
Firstly, a general note on 3D LOS. When attacking an square that is on a higher level with area fire you count as being able to see that square if you can see the edge or the corner of the floor. Assuming, of course, that there isn’t a solid wall blocking that side.
In terms of grenades, the Alpha already explains how to resolve explosions in 2D. Let’s add the third dimension.
This diagram is a side-on view of a grenade exploding on top of a single level block (B). Yes, it’s not a pretty sight, but them’s the dangers of dealing with Alphas 😉
The effect it has on adjacent squares (really cubes as we’re talking 3D) is as follows:
A: No effect. Grenades explode sideways and up, but not down. As the grenade will be lying on the floor, the blast will be blocked from damaging either square marked A.
B: No effect. If there was a hole in this square then there should be a chance of it falling through the hole (for the Alpha ignore this chance). If it does not then it can be assumed to be too far away for the blast to go down in much the same manner squares A are protected.
C: These adjacent squares on the same level as the explosion take the normal effect from the blast as adjacent squares.
D: If we assume that these squares are open on the side facing the explosion and that they are one level higher then they too are adjacent and subject to the normal rule for blast effecting adjacent squares. Remember though that as any potential targets will be higher than the source of the attack they will count as being in cover and so will get an extra dice.