These are the FLOSS games that stand out, list your own favourites or most-play games.
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I would rate all of these, as worth a try:
Shattered Pixel Dungeon
Cube2:Sauerbraten
SGT-Puzzles
Andor’s Trail
AssaultCube
Minetest
Neverball/Neverputt
PowderToy
0ad
Fillets-ng
Anuto TD
Xmoto/Bloboats
Flightgear
Kobo Deluxe
Enigma (oxyd)
LiquidWar5
H-Craft Championship
Numpty Physics
Wesnoth
The Dark mod
Have completed SuperTuxKart, BlobWars 1&2, Flare, Frozen Bubble, Hex-a-Hop, Holotz’s Castle, SearchAndRescue II, Alex the Alligator, Project:Starfighter, Stormbaan Coureur, Trigger, all are fun.
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Can find details about most of the above games here:
https://libregamewiki.org/List_of_games
FLOSS gaming is excellent, thanks to all these devs and asset creators.
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BONUS TOMT:
I’m looking for the name of a FLOSS Quake1-mod, puzzle game, that was about placing gravity points, to curve a stream of particles around the level, and eventually into the goal target. (May have used irrlicht) If anyone knows the name of this one, please let me know, it is my white-whale of games.
For anyone who likes the idea of CDDA but bounced off its vertical difficulty and complexity curves, there’s also Cataclysm: Bright Nights. While Dark Days Ahead chases realism, BN is a fork that prioritizes fun.
It adds a ton of quality of life tweaks to make basic tasks less annoying, and removes most of the artificial restrictions DDA added to make the game more difficult. It also lacks the pockets system that DDA implemented that splits your inventory into a dozen smaller ones, so managing your inventory is a hundred times easier in Bright Nights.
It’s kind of unbalanced, is missing a bunch of content that DDA has, and is much easier than the base game, but IMO it’s way more fun. And once you’re comfortable with things, you can move on to the base game for a real challenge.