Space Encounters only works correctly with the last revision of the 8080 mobo. Rev K, IIRC? The board also has the unused solder pads for larger EPROM sockets than all the earlier rev boards..
It has a couple very unique circuits to create the trench and the white screen flashes. Any 8080 mobo will basically work, but you won't see the trench or flashes, so SE is unique in needing the specific main board.