I love the three shirts, maybe jsut for the first one, make things more organised like an actual ski hill.. maybe give names to the runs.. like things to do with new schoolers, some inside jokes or something, i dont know.. maybe at the top of the shirt have a ridge and then it says "to chads gap" or some ns jokes liek that.
for the second one i'd make it darker and maybe include something with transparency on the wall, or sut simply make the whole design darker or like bright colors on a white shirt.
and the third one is awesome, but maybe make the guy lighter so its easier to read??
Just a few ideas, but they look great!