However, you're limited to teleporting to places on your screen, and only places you could reach on foot. It will also zap any enemies around both ends of the teleport. It has unlimited uses, but a lengthy recharge time. The first is your only jumping option in the game, but has very few uses and can't do much to enemies.
Each can only be found on a specific stage.
A good chainsaw user can simply run into a mob of aliens and leave chunky bits in his wake, while anyone attempting to punch his way through the mob would simply get mauled between punches.
However, unlike the standard melee attack, you can move freely while using it. but so can the standard melee attacks, and those are less likely to get you killed or wounded. Complete with a big 'shoot here' fleshy part on its rear.