Micropolis
Created by the SimHacker team, this free and open-source game is based on the original SimCity. For those unaware of it, it’s a simulation game which allows you to plan out and build a city while also facing any consequences your actions might result in. And, sometimes, giant monsters.
How to install:
sudo apt install micropolis
Freeciv
As you may have gathered from the name, Freeciv is a clone of the Civilization games, albeit the earlier ones. This version supports up to 126 people in multiplayer, and has a load of mods and scenarios for you to play around with.
How to install:
sudo apt install freeciv-client-sdl
SuperTuxKart
This mascot kart racer includes mascots from all your favourite libre operating systems and software, including Tux, the mascot of Linux himself. This is a fun racer full of power-ups, much like your Mario Karts, Sonic Karts, or Diddy Karts, and it even has a story!
How to install:
Follow the instructions here.
Hurrican
This game describes itself as ‘THE ultimate Turrican Mega-Mix’, taking ideas from several instalments of the original franchise while at the same time expanding on its universe. It’s a side-scrolling run-and-gun game with a killer soundtrack.
How to install:
Follow the instructions here.
Pingus
A Lemmings-style puzzle game with little penguins instead. Basically, you have to guide the penguins through a level using a variety of commands you can give them, like dig, redirect, build a bridge, etc. Unfortunately, the penguins do not have any regard for their own well-being.
How to install:
sudo apt install pingus