Colorful World
A path puzzle with a world to travel — from the Pyramids of Giza to Patagonia, two hundred boards that each have exactly one answer.
Every colour has one starting dot. Drag a line out of it. Cover every square, never cross another colour. That is the whole game — and it stays interesting for two hundred levels because the boards get harder, not bigger.
Boards are generated and then proved: a solver rejects any board with a second solution, and any board a cheap strategy can clear. So a level is never unfair, and being stuck always means there is something to see.
All 200 levels work with no connection. The leaderboard is the only part that needs the network, and when it cannot reach it the game says so instead of inventing players.