I consider myself a "shameless casual" of a sort -- my aim is terrible, my reflexes are slow, I daydream, and my melee sucks -- but I've played nearly all the game solo and enjoyed it. As several persons above have said, it is a game that rewards meticulous pre-preparation to a huge degree -- every one of my boss battles has ended up as an undignified massacre (I was even sorry for the humiliating way Moder went down) but I put in a LOT of work to make sure things came out the way I wanted. You have great freedom in changing and tailoring the terrain in this game -- use it! Trenches, pits, and earth walls will save your skin since most enemies can't make any sort of a dent in them. For instance, when I went up against the Elder, I tunnelled clear under his altar and built a complete base underground there, with a portal, an upgraded workbench, a bed, and a forge. I had tunnel exits in all four directions and a deep moat around the altar a short distance away, so old Woody was just about helpless when he emerged; I stayed under cover and popped out every now and then to set the poor fellow on fire until he cashed in his chips.