I'd like to ask for recommendations for FLOSS (Free/Libre, Open-Source Software) games, playable on Linux or Android. I saw an old thread on this topic, but it's over a year old, so I thought it'd be okay to ask this year. Genre-wise, I'm pretty open. RPG, adventure, FPS, RTS, TBS, 4x, puzzle, sidescroller, platformer, single-player, multi-player, online, offline... whatever. I would prefer not needing to have original (commercial) game assets.

Fine print: I do like a good FPS, but, having played commercial titles on PS3 and PS4, I've found that the FLOSS FPSes I've tried just don't hold a candle to them. Also, I prefer having a short TTK (think: hardcore mode, R6S, BFV), and every FLOSS FPS I've tried has had a long TTK.

I've already played:

Linux:

• Wesnoth
• 0 A.D.
• roguelikes (currently have an active character in Angband)
• Ur Quan Masters
• Minetest
• bzflag (long ago)

Android:

• SuperTuxKart
• Pixel Dungeon
• Andor's Trail
• Mindustry
• Pixel Wheels
• Vector Pinball
• Minetest
• Wesnoth
• HyperRogue

What I haven't played, but might check out:

• FreeOrion
• Endless Sky
• Glest, MegaGlest
• Warzone 2100
• Zero-K
• KeeperRL
• OpenRCT2
• Oolite

For those of you who may be too poor to afford the latest AAA titles, or just don't want to support policies like micro-transactions and "If you're offended, just don't buy it", there are many open-source and/or free games that can tide you over. Some of my favorites are:

• FreeCiv: A civilization building game based on Sid Meier's Civilization 1 and 2
• OpenTTD: A transport network building game based off of Chris Sawyer's Transport Tycoon Deluxe
• Dwarf Fortress: Not Open-Source - fortress colony management simulator with an additional RPG gamemode

Do you guys have any other free, possibly open-source games that you would recommend?

I've found a few really, honestly fantastic open source games and I'd like to share them and discover some new ones too.

Firstly, NullpoMino is a fantastic cross-platform Tetris clone. It's highly, highly customizable and is lots of fun to play. It's got a great community over at Hard Drop, and if you like Tetris - you'll like NullpoMino. However, there are a few issues with it; one in particular being the relatively low skill ceiling of Marathon. The skill ceiling is very low (compared to other titles such as the NES edition), but this is solely exclusive to Marathon as far as I know. It turns into a test of patience rather than skill. Another issue is with installation; as the game was made for 32 bit systems it is rather slow, and it's finicky to run on Linux. However, it is a fantastic Tetris title (and open source!)

Another good open-source game is Osu! I've never played it competitively, but it's a fair bit of fun to play with friends and is a great game. It's cross-platform, although I've only ever played it on Windows, and it has a nice community. Fantastic game that I don't see mentioned too much.

The last game for this post is SuperTuxKart. It serves as a great kart-racing game, that's fun and has a low barrier to entry. Graphically, it's not drop-dead gorgeous, but it's not bad at all either. It's decent solo, and a lot of fun with friends. Would highly recommend. Cross-platform and available as a snap.