In pixel Pixel Pirate yours sails are off - they are at angle to boat -which is necesary for gameplay but looks really bad - maybe if you get rid of sails and replace it with only ropes or rolled up sails it would be better. Also movement mechanic is bad - you have to consider accelerations and handicaps (you are considered jumping just after falling but also if player press button just before connecting to platform he should jump).
Canyon race is kind of nice but for me you chose bad colours - it isn't obvious for my eye if hole is hole or maybe rock. But that one is really fun to play :D
As for rpg mock-up grass looks odd on roof if that house also have normal roof.
It's nice that all of mock-ups are so much different. I'm curious what you will do with isometric.