There are actually other choices for romance, but you'll need to unlock them by earning the codes to do so from completing the other character's endings in order.
As a visual novel simulation, Saccharine is a little rough around the edges, mostly in that its UI feels clunky, and certain aspects of its plot are definitely rushed.
Just don't expect a traditional happily ever after, either...
So I played this with a fellow game developer and some other friends who have a lot of visual novel experience.
Having read about other routes, it seems like there are some very interesting narrative approaches, but the way the game has presented itself to me thus far doesn't make me want to engage with it anymore.