I'm not exactly sure what's going on, despite having lights in my level - after compiling and viewing in HL2Ep2 everything is fullbright. No leaks. All compile options are "normal". I've restarted HL2Ep2 many times, tried copying the map into a fresh VMF, tried compiling another map - to no luck. I have absolutely no idea what is wrong and it's extremely fustrating me.
Edit; if it helps, there was something odd that happened. When I had one map loaded (fullbright) I tried checking the main game - clicked new game, and in the background I noticed my level went "lit" for a second before it started to load the Ep2 first level.