I just finished the game and I'm ecstatic with the quality of writing and art, for me it's the best visual novel I've ever read without a shadow of a doubt. Please take as much time as you need, and I sincerely believe that not only me, but many people are eagerly awaiting the sequel, even if it takes years to happen, we will be here for you.
There's no sequel because Pervader isn't done yet. The next part has some tricky writing in it and he was unhappy with it and felt he didn't have the skills to do it justice, so he moved away to focusing on his art and improving his skills. He started something called 'horny gael' which was going to be a sort of nsfw roguelike i think? It's been like years since so i can't remember but anyway i think giga got burned out on it or didn't find it helping his artistic creativity flow and stopped.
Either way don't expect an update within the next year or two.