Moving around in 2d would be extremly restrictive. A 2d creature would have no semitry and therefor would be incapable of ever turning around and walking the other way. A 2d creature would therefore be unable to stay in 1 place on ets own and so a 2d animal would oventualy reach a place et could not live and be unable toturn around and so would die. Even a 2d fish would have to swim upside down to change durection in a 2d world and fish hardly ever swim upside down. 2d animals would probably need to come in 2 forms each whith opposite dimensions from each other. 2d creatures would probably have alternating generations were some would be born facing one way and others born facing the other way. 2d land animals would probably always be born facing in land if born on the coast, while 2d sea creatures would probably be born facing out to sea if born near the shore. 2d creatures would probably also have a hormonal memery telling them the last generation there ancesters were at the end of there habitibable range and if they were at the end of there habitibable range again. When they would get to the end of there habitibable range the hormonle memery would be recet. The way the hormonal memery would probably work would be that the consentration of sertain chemicals would increase over the generations if organisms were facing one way and decrease if the organisms were facing the other way and some chemicals would tell them when they were facing each way and if eather set of chemicals were to reach a certain consentration or if the sets had the same consentration it would mean they would be at the end of there habitable range by the next generation and so the next generation would be born facing the opposite direction as they were.
For 2d nomadick humans it would probably be even tougher because there children would have to stay with them for half of there lives and have reversed dimensions from there pairents meaning for 2d children 2 move whithout geting seperated from the group one adult would need to cary the child ahaid of the other addults and then lett the child run back to the other addult(s). Annother thing about a 2d child would be that the child would never see his/her father because his/her father would have the opposite dimensions as his/her mother so that his/her father would have to move away from his/her mother after seeing her so the childs mothers brothers would probably be the childs father figure. In order for 2d humans to settle down into a non nomatick society they would have to cary people of the opposite dimensions to the edge of the comunity and then allow one of them to return the favore. Another problem 2d humans would face would be that if they were to try to build a city the city would need water and if they were to try to transpert the water through pipes the water would seperate the top of the pipes from the bottom of the pipes causing the pipes to cave in so they would need to have doors that would open and close as the water would flow through and that would open at different times from each other to hold the pipes together.
Another problem for a 2d land animal would be that if et were to come across a tree as would be inevitabe in a farest would be that the animal could not go around the tree et would have to either go above the tree or under et. Some animals are to big however to go under a tree or to climb a tree so the tree would have to be strong enough to not bracke as the animal would go over et.
2d animals would also only need a number of leggs that would be a multiple of 1 because they would have no sides. This means that most mamals and reptiles would have 2 leggs and humans birds and some dinosaurs would have 1 legg so humans would hop instead of walk to get around. also humans would only have one arm on the front of there body so they could not touch there back side, and would have trouble reaching certain parts of there bodies as there hand could not move around very much in 2d as et could only move up and down and bend to move forward and backward.
It would also be impossible for 2d techtonic plates to change possitions as they could not move past each other and so there would be no continintal drift.