The HAPP is short for Habitat and Animal Protection Program. Join the HAP to save the enviroment and do crazy missions. Also before the whole thing happened you've been given armor that lets you take no damage. Its basiclly easy mod in a nutshell (did I tell you that every next boss will have double their health from the previous one?)
Next Update also includes: 3 more missions, a new character, and 2 more bosses