Usability is one of the most important characteristics of software applications especially when it comes to mobile shopping applications. There is a great deal of shift from traditional shopping to online shopping because it benefits both parties i.e. customer as well as businessman. A customer just has to download an app to access a wide variety of products and product is at his home within span of two days at maximum while businessman benefits from millions of online shoppers who other- wise are not able to a physical store for any reason. The number of app downloads the number of active users and the number of online transactions is directly related to annual revenues of business. In such scenario, usability factor can play a very vital role for business industry. If a client stops using a mobile shopping app because it is not user friendly, it can badly damage the annual revenues especially when hundreds of alternatives are available and there is a tough competition. Therefore, to keep existing customers intact and to attract new customers, it is very important to provide a user friendly and confusion-less mobile app to customers. Any minor design flaw can result in million-dollar loss in the long run. In this scenario, it becomes important to identify the real usability problems in shopping apps and to propose domain-specific design heuristics for mobile apps developers so that better mobile e- commerce apps could be developed to keep their customers engaged in the long run. There is a large variety of online customers with diverse requirements. Background and constraints and there is a need to evaluate usability of existing mobile ecommerce apps with diverse type of customers to identify the actual problems people are facing with existing applications. In this paper, we conduct usability evaluation experiments on large scale (i.e. 1080 total experiments) with a diverse category of participants on a sample of mobile shopping apps. We identify the actual usability problems people are facing in existing apps along with proposal of domain-specific heuristics for mobile ecommerce apps. Besides this, we provide a detailed systematic review of mobile ecommerce apps.