I would like to point out that the Boomerang goes a certain amount of spaces. Im not sure how many but here is an example. Also lets keep in mind that the coding has yet to be perfected ok. Lets say the Boomerang goes 6 spaces and comes back. If you close the gap of 6 spaces so that when it comes back it only travels 5 spaces or well anything less then 6 it will hurt you. The plus side to this you cant kill yourself with the Boomerang. The downside to this is if done enough you can give yourself negative hearts and will die instantly with a bad guy or going for a swim in the deep part of the water. So for now hows about when you use the Boomerang either stand still or move backwards, just not forwards.
HarvestReaper