I take a lot of inspiration from video games but I want to make creative tools. What's the difference between a game and a creative tool?
One big difference seems to be the end goal: with a creative tool you make something you want to share outside of the tool. You export something, often an image or a text document. In a game, you're normally working within the game world. Often you're completing quests. For more creation-oriented games like Minecraft, you're building something and you may even share your creation in the form of screenshots or recordings, but still there's a sense that what you made belongs in the game world and is best experienced there.
Another big difference is primitives. In drawing and painting applications, you're often working at a pretty low-level, defining shapes and colors and paths. In games, you're often acting within a world using an avatar. It's more like making scenes with dolls and action figures (or in Minecraft's case, legos) than it is painting or drawing. The distinction seems to carry over pretty cleanly from the physical world. 3D graphics programs or game development tools like Unity possibly make things a little fuzzier, but even there I think the distinction between playing and creating can mostly be classified according to what level you're intervening at.