I just finished G-Senjou no Maou and I really enjoyed it. I must have put around 30-50 hours into it. I wasn't expecting much, but I really enjoyed the characters and the twisty story. I think anyone can enjoy Visual Novels as long as you don't jump into them expecting an actual "game." It has choices which influence the story, but they're only three which actually branch you off into different sections. Great game, I recommend that people at least give it a look.

Also the soundtrack is super awesome