I’m incredibly frustrated because I can’t get a straight answer anywhere. WHAT DOES IT MEAN? Is it contrastive, or not? In some sources, it says it is used to simply connect clauses (The first clause being an introductory phrase for the second) and in other sources it implies it having a contrastive purpose. If it isn’t contrastive, then what is the difference between it and で for connecting sentences? And if it is contrastive, HOW does 新しいゲームをやったんだけど本当に楽しい(sentence taken from a video on んだけど) translate as ‘I started playing a new game, and it’s really fun’ instead of ‘I started playing a new game, but it’s really fun’? If you are going to explain this, please give a lot of detail because I have been incredibly annoyed by this and the lack of explanations I’ve found for it.
んだけど can be divided into ん, だ, and けど.
As for んだ, it's a colloquial form of のだ. This の is difficult to grasp at first because English has no direct equivalent.
- Wasabi: Explanatory のだ (んだ) (see the "preliminary remarks" section)
- What is the meaning of ～んです/～のだ/etc?
けど basically means "but", but it is also used to give a background or introductory information before diving into the main topic:
There is no contrastive meaning in your sentence. This けど is just there to indicate that "I started playing a new game" is an introduction of your story.
けど（けれど、けれども）has two meanings. The first much the same as のに, meaning 'however, but'. The second meaning is 'and also', so this word is not exclusively used in the adversative sense of 'but' (compare が). In your example 'and' is appropriate as a translation. This has nothing to do with the のだ which ends the first sentence (clause). Martin (Reference Grammar) says that sentence + のだ is especially common when some kind of reservation is expressed, or implied, e.g., 行きたいのですが...'I want to go, you see, but (may I? can I?)'. Your example would fall into this category I think, 'I've just started a new game (you see) and...'.