There will be no such things. Lags already announced a wille ago the enemy's you will encounter in the final version. More stuffs means more work for him and already from my point of view,to re-make the game from 0 after you finished it is stressing and annoying at some point,my opinion. There will be some special enemy's but nothing more. But the idea of aliens and etc can be used for future games in his list,as for the next 7-9 months till Hailey game gets finished,will not see em. But I hope lags will use some old concepts in future games as gallery images or animations as they are a succes in each game. If SurVive had animations too and a platformer type gameplay like Hailey adventure has, I guess was another outstanding succes,as it is already a succes from gallery point of view and exploring part, even if it is static.