Warzone 2100 & Jets'n'Guns (Gold)

Both games work without any problems on N10.

"In Warzone 2100, you command the forces of The Project in a battle to rebuild the world after mankind has almost been destroyed by nuclear missiles.
The game offers campaign, multi-player, and single-player skirmish modes. An extensive tech tree with over 400 different technologies, combined with the unit design system, allows for a wide variety of possible units and tactics."
The game was released in 1999, but went open-source, so it can be found here: http://wz2100.net/
For Mac, Linux & Windows.

"Jets'n'Guns (also shortened to JnG) is a 2D, side-scrolling shoot 'em up computer game released in 2004 by RakeInGrass software."
If you ever played Tyrian, then this one will feel similar. You gain money by killing enemies, and between levels you upgrade your ship and weapons. The difference (compared to Tyrian) is that there are many weapons to choose from (doubled in Gold, along with levels) and there are no lives; you come back to the beginning of the level if you get KIA along the way, and you can try the level again with different weaponry. The game is funny in most aspects (shop, designs, "gore").
The soundtrack was made by Machinae Supremacy, and there is even a level in which you raid their concert!
This one is again available for Mac, Linux & Windows. But it ain't free.