Yeah, you could space the blocks apart by a few more pixels, or you could make the collisions slightly smaller. You will probably have to wait until the jam is over, since the submission period is done, though.
All tiles through the game is 16x16 testyed making a hitbox with the size 14x14. and with that it gave the slash 2 more pixels to the sides. so you could kill enemies through walls. so now i need to make the slash 14x14 aswell. Should work.