Thanks a lot, everyone.
Working on animated tiles recently, also did a lot about level editor and I'll publish a new dev log soon.
As you can see, both synced (waves) and unsynced (flowers) animations are supported.
TileAnimation system tracks all tiles which need to be animated, and when it's time to change a frame, it updates needed vertices in vertex array.
Level editor looks like this now:
* Added a toolbar. Previously tile editor had "three modes" - tile creation, entity selection, entity creation. Now I can easily add new tools!
* Empty tiles can't be selected for tile brush, also non-first animation frames for animated tiles can't be selected too
* Added tile layers.
* "Tile stamp tool" lets me combine tiles into "tile entities", e.g. house is a big stamp which can be applied to create new houses easily:
* Finally started to work on the second level - it was not easy to make sure that new level loads correctly and everything works well (there's a very elaborate scheme to find out which prefabs/entities are needed for the next level):