d={{{1,1,1,1,2},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1}},{{1,1,1,1,2},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1}},{{1,1,1,1,2},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1}},{{1,1,1,1,2},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1},{0,0,0,0,1}},{{2,2,2,2,3},{1,1,1,1,2},{1,1,1,1,2},{1,1,1,1,2},{1,1,1,1,2}}};

p=ArrayPlot3D[d,ColorRules->{0->Gray,1->Blue,2->Red,3->Green},OpacityFunction->(0.8)]