get bushidos explosives from tier pack and make mines with the stick grenade explosion. make it lower than it is and there you have a mine. also you could add some exploding gas tanks and some clouds (do this by making smoke in the air with elevated 64x baseplates) also make some hills you can clime and if you want pitfalls would be cool. you have to mark them with discolored ground or some 1x1s over the pitfall. also since you can build underwater now you should go and build under water.