For starters, I play this game offline. I wasn't a fan of Harvest Moon, so I was put off by this game for a long time. I wasn't interested in "wasting time" in another fruitless game, trying to achieve something for nothing. My best friend loves this game and it was she who is responsible for me buying this. Granted, I whined about it, but I bought it nonetheless.
This game feels closer to Minecraft than it does Harvest Moon (I never played Terraria, sorry). It has something for everyone to enjoy. It teases you with new areas to explore, secrets to uncover, and skills for you to unlock. Stardew Valley allows you the freedom to do these things at your own pace. To break the monotony of farm life, you'll have town activities, side jobs, and quests--- all optional but worth doing.
The problems I have with this game comes down to certain mechanics. I don't like the save system. You save by sleeping. If you accidentally ate a rare fruit you meant to get more seeds from, you'll have to exit and restart the entire day. The rewards you get from bundles don't always make it worth it. Thousands of gold for a lightning rod when it rarely rains in my game? The writing at times is hit or miss, why give me the option to tell people about a secret I can't do? A certain character regressed the moment I married him, even after reaching 14 hearts. I also found the unlocked areas underwhelming after the first time exploring it.
I'm still hungry to do and see more of Stardew Valley. Ape has done an amazing job with the game thus far. The modding community is the icing on the cake.