Welcome to the wonderful world of endless possibilities of DF!
One of the most replayable games I've ever met. Once you start to figure out how to make custom traps (using pressure plates, mechanisms, trapdoors, collapsible columns, screwpumps...etc) to make rebuildable outdoor ceilings that can be collapsed to crush enemies (good for large attacks) or a magma flood chamber, or a trapdoor grid that drops enemies into a pit in which you keep a dragon or titan....so many things you can make in that game.
I could geek out about it for hours.
I've made some really fun and elaborate traps in some of my forts, but I never save them because of updates. I had once uploaded a video of one of my traps at work...hmm...I'll see if it's still out there.
(edit: guess I didn't save it, oh well. Basically it was this island that was connected to the rest of the ground by a hatch. There was a winding path made from floodgates that wound in a serpentine pattern with 'bait' at the end of it to draw enemies (a chained up dog was the bait). The winding path made sure that it took them long enough to get to the bait that most of the enemies would be on the island. When they got to the bait at the end of it, there was a pressure plate which served to open the hatch, thus stranding them on the island. Once that was done, one pull of a lever dropped the floodgates and they were sitting stranded on an island helpless, where my archers could march out and easily slaughter them. I loved using that one.)