I will start this by saying that the dev will likely never update this game again as he is working on other things. That said,
1. Yeah there's no way around that. Maybe run the game in a smaller resolution?
2. Have you tried using different texture packs? You can change the texture pack used in the settings menu. (You can also make your own texture pack. I made one and there's a link in this thread: https://itch.io/t/146790/update-070)
3. You can just make it windowed and make it big, this is the only solution I have found.
4. There isn't a way around this one, unfortunately.