The main feature - it was necessary to show different product's structure based on user's choice - table or icons. I solved it by adding a few blocks through views php-code, which are saved user's choice via session and printed appropriate view. Everything else was standard for typical online shop.
On the whole, at this project I also had learned to not only work as a programmer, but also as the manager - without clearly formulated Statement of Work I eventually did not cope with this project and delivered it to another developer. Since that i always rewrite Statement of Work by myself, or pull it out of the customer until i understand the whole volume of upcoming work.