Yes, you can host a game on LAN. You have to share your local IP (not router IP) to your friends, then they can connect.
Hello Creeperkiller09, thank you for your feedback. Can you tell me what options you have selected in the world creation menu? Many options aren't optimized yet in this early version, e.g. erosion effect, it needs huge cpu power. Please start a single player game without any options and tell me your experience. And can you tell me your computer specs (CPU/GPU/RAM/OS)?