There is some cool stuff that works only on API 21+. Some of it is pretty easy to imitate on the older APIs, some is included in the Support Library, but about others I have no idea what to do. E.g. so called "Shared objects" when there are some corresponding elements on 2 activities those act as one while activities change.
How is it done on pre-lollipop devices? Or what tricks do good developers use in similar cases?
Shared elements are not available pre-lollipop. you can imitate them but its not easy.
you can see this video that replicates it