The game is not bad, and the renders are excellent. The grind though, is terrible. I couldn't play without the mod past the 1st 1/2h.
With the mod, it's much better. You just concentrate on the character grind which is OK for such a sandbox game.
About the file size, have you played The Twist? Graphics are more compressed than LM but uncompressed it is still 10GB and it's fully animated. The author of LM claims he would not compress the graphics to keep maximum quality, however I am sure that a 50% compression would hardly have been noticed.
I'm kind of glad this is over. I liked the scenes and the progression (and yes I'm an anal freak) but if the story continued for too long it could have easily been just boring new scenes.
The author can start making to make a less grindy game now.