Shovel Knight: Specter of Torment

My preferred stage for this one is the Plains, because the enemies are fairly weak and easy to kill without too much difficulty. The challenging part of this stage is the boss fight against Black Knight. However, with a bit of practice, it is possible to essentially corner-lock him for easily 90% of the fight. If you are very lucky, maybe even the whole fight. As soon as the fight starts, what you want to do is to start dash slashing him from the left side and push him into the corner. The next part takes a bit of practice and luck. At this point, you just repeatedly dash slash him either until he is dead or he decides that he doesn't like being in the corner anymore. Also, if you accidentally dash slash his mount, Terrorpin, when you have him in the corner, he will usually rush out of it.

See Scythe Economy for a video example of this.