Would you theoretically switch to another engine if you had the ressources?

my opinion is this: java is a well documented and to be honest the most used and popular of the oop's the engine they are using is unity the oop (programming language) is java.not that other languages aren't flexible,they are but java is and has been king if you will and most likely will continue to be for at least the next ten years.....also some of the most popular games are written in Java

I'd say stick with Java. It's cross-compatible with just about every system. Heck, even televisions and mobiles, to a point.

I'm pretty impressed with what they have accomplished with Java so far. The game looks pretty (besides the player model) but I'm sure there is even more they can do with time.

As much as I hate the living hell out of Java, there is nothing really out there at the moment that surpasses it's flexibility and cross-platform compatibility, even if it is extremely buggy and unreliable more often than not. Not to mention it can be rather inefficient under some circumstances... but fortunately this game seems to be reasonably well optimized, even as an Alpha.

I can't really imagine attempting a project of such an unconventional nature on a mainstream engine like Unreal 4 or CryEngine, etc. I'm not a programmer, but I'm sure the block-building system and dynamic terrain functions would require at least some source code modification on any engine that you choose. Mainstream FPS platforms aren't exactly built with those features in mind AFAIK.

Though I certainly wouldn't complain if they *did* somehow manage to upgrade to UE4... So long as that didn't involve the better part of a year spent recoding everything.