I have an alien that shoots a laser. A line is drawn from the alien xy to the botom to represent the laser, but how do I check for collision?
"Queen and huntress, chaste and fair,
Now the sun is laid to sleep,
Seated in thy silver chair,
State in wonted manner keep."
yes, learn about vectors. They are easy in 2D and 3D. You a plane intercept equation to determine where two planes intercept one another. This is how "real" games do it, after they've done a brute force check for bounding-box collision, or HSR culling.
It is not the spoon that bends, it is you who bends around the spoon.