Well the terraining sure looks nice! Triggering is my forte however. Combining elements is still pretty vague. What are these elements exactly? Items? Units? How do you intend to combine them? I.e through a spell etc.
If we're starting with four basic elements, we need to decide how the effects are put together. For example, do fire and ice make a FireIce element, with just both characteristics glued together, or something entirely new? I'm just speculating here. I'm not sure what your project is at the moment hehe