The new engine brings with it new improvements.
The hit indie survival horror game, The Forest, has seen an upgrade to its engine, to Unity 5, it was announced today.
The change in engines brings with it multiple changes and improvements to the graphics as well- the plants and skin shaders have been rewritten, and many other visual tweaks, now only possible because of the new engine, have been made.
This shift to Unity 5 comes as part of the 0.61 update to the game (as the version number suggests, the game is still pre-release, and is in fact only available on Steam Early Access). Apart from the gameplay and performance improvements, there are also changes to the gameplay experience- multiplayer gameplay should be better thanks to a new network prioritization algorithm.
Unfortunately, all of these changes have come at a cost- the environment has been largely re-written, and all save games have also been wiped.
Still, this is part of the territory when you offer to play-test a pre-release game. And at least the improvements here are regular and substantial.