I would like to use some features from Steamworks SDK but some of it isn't in the engine and have to include separately.

Things like Matchmaking, Server Browser, Stats, and Achievement.

Is it possible to add all features from the Steamworks SDK into the Esenthel Engine instead of having to include separately?

Hi,

At the moment your best option is to include headers/libs and do programming manually.

Alternative option is to do the same with the source license, there you have access to existing steamworks codes, which should be easier to work with.