Yeah you could do it like that indeed.
But of course you have to know that even if Mario is just touching the wall with his head, Mario will be tranfered to the top of the block with this code.
I recommend using non-solid objects. Of course they would be a bit more complicated.
OH! And enemies won't react on this either

Doesn't work.
Example: Make Mario jump through a block from below and an enemy standing on this block will fall down. Therefore this doesn't work.
Non-solid blocks is the key to make them perfect or even "good".
But this takes a lot of GML knowledge and can't be explained in a post.
Maybe some day on MSN *sigh*
This post has been edited by Guinea on Jan 27 2006, 10:42 AM