OpenTTD

OpenTTD is a free, open-source business simulation game based on the classic 1994 game Transport Tycoon Deluxe. You build and manage a transport company across a procedurally generated map.

What you do Connect cities, industries, and resources using trains, buses, trucks, ships, and aircraft. Buy vehicles, lay track and roads, build stations, and optimize routes to move cargo and passengers efficiently. You earn money, expand, and compete against AI companies.

The core appeal It's really about logistics puzzles. Building an efficient rail network that doesn't deadlock, timing signals correctly, deciding which industries to service first — it rewards careful planning and gets deeply complex if you want it to.

Trains The heart of the game. Rail building has a huge skill ceiling — junction design, signaling systems, and network optimization can get extraordinarily complex. There's an entire subculture around building efficient "junctionless" networks or massive hub stations.

Why it holds up

• Moddable — thousands of vehicle sets, landscape packs, and industry mods (called NewGRFs)
• Multiplayer — cooperative or competitive on public servers
• Still actively developed despite being 30 years old as a concept