I got almost all of the achievements and collectibles I couldn't figure out the score a field goal one and commit regicide.
For the field goal achievement, you need to fling someone through the football net thingy. go to the water tower, then turn left; you should see something that looks like a fork with yellow poles.
If you also don't know how to get the Regicide one, just find the person with a crown then kill him how ever you want :3