Cheap alternative with potential for improvement

Delivery took place within 3 working days.

The size of the garage is ideal for collecting lawnmowers.
The second copy is used for storage of garden chairs.
After building turned out that the whole structure looks rather a bit shaky.
Must be so fixed in any case at the foundation is. Mounting hardware included.
Price / performance, so far, completely ok.

Now to the point deduction:
The zipper at the opening is not revolving. Below is always a gap (full width), can penetrate through the water and vermin, as only a zipper on the left and one right.
Possibly you can or similar here with Velcro help.

Actually, the garages were designed as all-season solution. If that's possible, the first winter will tell.