Freestyle is generally forward but can be styled many ways including back. The crown is not defined but it is somewhere near the center line, and there are no gaps or partings. Freestyle is the most popular choice and can be used as a starting point for most hairstyles
Pompadour Freestyle as seen here on Sean Connery and James Dean, is similar to Freestyle in that there is no defined crown and the hair on top comes forward, but then at the front it elevates. With long hair length this creates a Rockabilly look, and with short hair it gives a neat top with a fashionable spiked up hairline. There are many variations possible with a Pompadour Freestyle unit.
Spiky usually means all the hair stands up and is directed away from the scalp. It can look punky or it can look militaristic depending on the amount of texturizing product applied, and on the length of the hair. With curly hair, it can give an elevated riot of curls. In actual fact, the factory treats spiky orders in much the same way as freestyle orders, because the spiky effect is not part of the manufacturing process, but rather part of the wearer's haircut and styling.
Center crown, left crown and right crown have a defined crown. All the hair is directed away from one point, either in the center of the crown or to one side, and therefore you will always see bare scalp at the crown point. We usually boost the density a bit at the crown point so it does not look too bald in that spot, but if you don't like that spot to be there, get freestyle instead.
If you order back, or comb back or brush back or flat back, all the hair will be back and there will be no crown.
Left part, right part and center part feature an open parting along which you can see the base or the scalp through the base, depending on if it's lace or a skin base. The parting really has to stay in the same place where the factory puts it and it should not be moved to either side afterward, because special knotting and density considerations are designed into the hairpiece.
The generic style illustrations above are for descriptive purposes only and do not depict actual hairpieces. The style/direction you order is your starting point for the final hairstyle that you and your stylist create. Hairpieces come uncut and unstyled and always need to be cut-in.