To put it simply, Barotrauma is a great game. Sure, the singleplayer is pretty abysmal. Bots aren't terrible to play with, but you can only do so much by yourself. If you're looking to play solely by yourself, then sadly this isn't the game for you, not yet at least. Multiplayer is the main shining star of the game. Randoms can be terribly stupid or even trolls, yeah, but there's plenty of people who want to actually play the game and have fun. Trolls are few and far between compared to how many people you see, and stupid people are ultimately just new players for the most part, so that's more than a reasonable excuse for being stupid.
The campaign can be redundant at times, but what's nice is you can use any sub around, whether it's a vanilla sub or user-made. The campaign only really starts becoming somewhat redundant towards the end, but even then, it's ultimately what you make it. You can take it at your own pace.
I haven't even mentioned the sub editor yet. The sub editor is it's own beast in itself. It's a hidden gem in this game that can be incredibly enjoyable. Whether it's just making a sub from scratch or just screwing around in the editor, you can't go wrong with it. You can easily spend a hundred hours in the editor alone.
Whether you're trying to finish the campaign, building a sub in the editor, or simply just ♥♥♥♥♥♥♥ around with friends or randoms. This is a game worth picking up. If you enjoy working together with others, it's a great game, as long as the others are actually cooperating. You can really meet some great people.