First Encounter

[Azarien]

Is it possible to run singleplayer campaign from First Encounter?

I was successfully able to run Second Encounter (Steam version), but when I copy all the files from FE in the same way, I get errors: it still looks for SE specific files (like Levels\LevelsMP\1_0_InTheLastEpisode.wld).

[SLAwww]

The path that you mentioned (Levels\LevelsMP\1_0_InTheLastEpisode.wld) is a default value for game startup script. When you copy all the files from The First Encounter, don't forget the "Scripts" folder. It contains proper paths to startup levels.

[Azarien]

Sorry for the late answer, but that doesn't help. It seems that this source code does not support FE.
For SE, I can replace the whole BIN folder and the game works.
Not so for FE.

So, did anyone succeed in running First Encounter with this source code?

[ptitSeb]

I don't think the First Encounter is playable with this code yet.
On my fork (https://github.com/ptitSeb/Serious-Engine) I added some files to have it playable, but only on Linux. I haven't messed with the Windows Solution to make it TFE build on Windows (it should be doable with not much effort).