Rectangle Collision

Well, surely doing checks such as:

if(rect1.y + rect1.height <= rect2.y && rect1.Intersects(rect2))

Then in this instance rect1 is colliding to the top of rect2. I could be wrong though, these things can sometimes be deceptively simple

Another approach would be to have 1 large bounding rectangle, and 4 smaller rectangles representing his head/rhs/lhs/feet. The large rectangle would be a quick check to see if anything is likely to collide, then depending on which smaller rectangle it collides with, you make the appropriate reaction to it.

These smaller rectangle idea could be helpful for things like walking on a platform, you only want "Gravity" to stop if his feet are collding with something etc.

Ya I have it the first way but its difficult. And considering this is for a platformer your second idea seems quite good. Ill try it and see how it works. Thanks for the help.