This is factorio in a tower defense style scenario. I'm still working on it but it's playable and hopefully enjoyable.
Biters will march on given paths straight to your rocket silo, you cannot build on the paths but you can build turrets and fire at them. Of course you'll also have to start mining resources to supply ammo and make more turrets.
It will take about an hour or two depending on the difficulty level and wether you can live through it. It currently wont work in multiplayer, I intend to change that eventually. This scenario is intended to be challenging but difficulty levels exist because players will come at many different skill levels. Balancing is still work in progress but the intended difficulty for veteran players (whatever that means in factorio) is very hard.
It was intended to feel similar to a campaign level as you might find in RTS games like starcraft. As a result it is faster paced than sandbox mode and the factorio campaign levels and you will be entirely focused on building your defenses and holding off waves. The closest analogon is the wave defense scenario in vanilla, though this one has a few twists of its own.
How to play
The scenario is packaged as a mod. You can start it by selecting from the main menu: Play -> Scenarios -> Tower Defense/towerdefense_basic. The scenario is almost entirely vanilla but it does include rocket turrets and as a side-effect of enabling the mod you can build those in the normal game too.