The order summary/Shopping cart that shows every time I add something in the cart, and I have to press the continue button should be removed. This is annoying and totally unnecessary.
Remove this page in the normal flow.
If the user wants to modify the number of articles or see the cart summary, he/she will press the shopping cart.
The current solution nearly on stops the user from buying different products, if you dont believe me, just try to buy 20-30 different articles and see how annoying it is.