Slopes. One of those typical newbie's problems.
This example shows you a well commented way of making perfect slope movement.

Just a nice platform engine of .V. Platform series standart.
Includes similar animation engine, unlagged collision system, moving platforms, keys & doors, sample enemy, collectable things and some more.

A example of script for detecting tile positions in isometrical grid.
Usefull for building pathfinding systems in iso worlds.