Well I've been poking around and man, there are some bugs in it. Did you notice Keen must fall after he shoots in midair? (This is very easy to fix, but they coded something special in Keen's tile collision for it.) Landing isn't in tile collision, the pole grabbing code is a separate subroutine, something that carries through to Keen Galaxy... so many inefficiencies...
It may actually be rather simple, if involved to patch in a death property.