This thing's called "XkySprite" because it's based off some drawings I submitted to cc314 when I was a senior in high school... Manboy did a pretty darn good job of replicating my silly little doodles--I just don't like how low Keen's shirt dips in the front.
Whenever any Keen sprite is made, the two sprites that a player is going to be looking at most, and consequently the two most important frames for the creator to focus on are the "standing" frame and the "mid-air-jumping" frame.
XkySprite's standing frame looks just fine--and the run works reasonably well. But the jumping frame just looks awkward: it works okay for falling off a ledge, but for a jump? It doesn't flow well.
On the side, the lack of black outlines make this sprite look out-of-place in many mods.
Overall, this is a solid sprite that looks much better than the standard Keen:Vorticons sprite--it's just not quite as good as the Keen:Galaxy sprite.