I tend to focus a bit on the 3D side of things, but the recently open-sourced Torque2D (note the "2") engine is pretty cool too:
And in fact it got a whole lot better in the last couple of weeks with it being ported to Linux, Android and your browser (through Mozilla's emscripten).
So if you are thinking about developing an open-source 2D game targeting multiple platforms, Torque2D has just became a serious contender.
Not only from the clutches of Ganondorf, but also from the dominion of proprietary software. All thanks to the magnificent Solarus Engine, a GPLed, SDL-based, 2D action RPG engine. This amazing project aims to provide a stable and easily customizable platform for users to create their own Zelda-like games, and so far, I must say, I am darn impressed by what I've seen. The engine already has two incredible launching titles, named The Legend of Zelda: Mystery of Solarus DX, and a parody of the former, Mystery of Solarus XD. Both are true love letters to the classic SNES RPG, The Legend of Zelda: A Link to the Past, and amazing and enjoyable games on their own.
Mystery of Solarus DX
But hark, the mere words of a mortal make no justice to the grandiosity of this undertaking. Sheathe thy sword, get thy green cap and ready yourself to adventure! You can start by marching straight to the Solarus download section, or, if your intentions are more creative, you can check the various sources here, and the quest editor here.
Code License: GPLv3 Mystery of Solarus DX Artwork License: Mixed (original Solarus assets under CC-BY-SA, but the game also uses spritework taken directly the A Link to the Past rom)
Here is a nice (but slightly older) game-play video for those not having played Xonotic yet:
Changes are quite extensive compared to the last official release... most notably an extensive update the the CTF mode, some neat additional features for competitive gaming and an assortment of great new maps.
New maps in Xonotic 0.7
On the technical side of things, the engine DarkPlaces got quite a few performance improvements (mainly due to the fact that the creator now works at Valve software and thus has direct access to Nvidia's and AMD's graphics hardware divisions) and that an all new script compiler is now in use. That it runs on SDL 2.0 might also increase it's usability a lot for some. There are also finally an animation bending feature for the player-models and creation of new characters has never been easier now that the iqm format is used.
Also check out these two still under heavy development mods for xonotic:
Overkill is a mod that attempts to combine the best of minsta gameplay and TDM/CTF. It also has some nice vector shaded new weapons and player models.
DotC is an DOTA like but in 1st person view type of mod.
Last but not least, the awesome all new level editor for quake based games, Trenchbroom is making great advances and should soon allow easy mapping for Xonotic out of the box.
P.S.: If you have a really fast Android device, you can also try to run Xonotic on it via this newly fixed DarkPlaces port. Just don't expect to be able to compete online with touchscreen input :p
Bushido Blocks is a puzzle game for Android under GPL license, inspired by block-bashing games such as Bejeweled, Diamond Dash and Tap Blox.
Bushido Blocks Screenshots
Tap matches of three or more blocks to slice them with your katana. The more blocks you can slice in one go, the more time you gain on the clock. Special blocks eliminate whole rows of blocks but don't give you any extra time, so use them wisely.
Erebus is a hack & slash role-playing game under heavy development, yet playable with currently three missions.
Features:
Classic point-n-click style RPG, with dungeons to explore, enemies to fight, NPCs to talk to, sub-quests to complete, scenery to interact with, weapons, treasure and other items to find.
Also supports Rogue-like keyboard controls.
Multiple quests (currently three, more will be added as development progresses!)
Choice of starting characters (currently Barbarian, Elf, Halfling, Ranger, Warrior).
Start straight into the action - none of this "For your first quest, please find your next door neighbour's pet cat".
Vector-based world rather than tile-based - so items/scenery can be placed in any position, or aligned in any direction.
2D animated graphics, with zoom in/out, and lighting effects.
Completely free and Open Source - no ads, unlike many free Android apps.
User interface optimised to work with mouse, keyboard and/or touchscreen.
Cross-platform - available for Windows, Linux, Nokia Symbian and Android devices.
Code License:GPLv3+ Content License: Various (Most DFSG approved, CC-BY 2.x might be problematic)
Physica is a very simple casual platformer game where the goal is to drive a square through game levels from its starting position to his goal, avoiding hazards and without falling down.
SkyRiot screens
SkyRiot is available for free for Android on Google Play and was released under open source and free content licenses on SourceForge.net [forum post].
SkyRiot is a 2D flying shooting platform action game for Android devices. Fly a hoverboard and use an assortment of weaponry as you, an anarchist, single-handedly wage war against a totalitarian regime. Full 360-degree aiming along with total freedom of movement will keep you glued to your device for many hours as you blast your way across over 10 game maps.
Otherwise, as previously mentioned, Garage Games has now also released their 2D game framework under the MIT license:
Their 3D game engine also saw some nice updates lately, however sadly their crowd funding push to port Torque3D to Linux fell (not totally unsurprisingly) short of their 30,000$ mark (with about 10,000$ pledged).
Looks like we will get some nice x-mas presents this year:
A bit delayed but probably right on time for the Mayan end of the world, we will see a long awaited new release of Cube2:Sauerbraten. Read about the release announcement here. Hmm, I wonder if it has already Occulus Rift support...
Also on the FPS front, AlienArena is having a major engine update, with a claimed massive 3-4 times speed increase in BSP rendering and more VBO improvements.
Furthermore they announce a new game-mode to be added soon, which tries to slow down the game-play of AlienArena a bit and add a more tactical appeal. Sounds a bit like selling out to the CounterStrike/ModernWarefare crowd to me, but lets see how it will play ;)
And in fact it will not only be a source-drop, but rather a significant update including a merger of their iOS code with the rest of the Torque2D one.
Also no Linux port yet, but just as for the 3D engine one will hopefully show up sooner or later.
P.S.: In case someone has missed it: SuperTuxKart had a very nice new release recently, bumping it up to version 0.8. See a video of it in action here.
Linus Torvalds not only showed his annoyance with Nvidia but also his love towards open source games in a recent talk (goto 58m20s).
ctdabomb, an active community member, converted and license-clarified the Art Museum SuperTuxKart racing track over the time span of about one and a half months, after asking the community for support.
SuperTux, a cute platformer, needs help finishing an animated owl sprite. To the left, you can see the current placeholder graphics.
FLARE, a hack'n'slash RPG engine and game, requested translations via email, pull request or forum post.
2012 February the 6th was the 10th birthday of Frozen Bubble's first release. The development was started in november 2001 by "ayo", amaury and Guillaume Cottenceau, members of the MandrakeSoft team (Mandriva nowadays).
Frozen Bubble is a beautiful game inspired by Puzzle Bobble (published by Taito in 1994 , also called Bust-a-Move). The game has nice graphics and music (from matths alias Matthias).
Frozen Bubble level editor for Android
Development has stopped in 2008, but Frozen Bubble and its ports still enjoy high popularity, especially on the Linux and Android platforms. A Java port also exists. Only the first version is available for Windows.
Phlipple is an original puzzle game which could be useful for training thinking in 3D.
It's available for Linux and Windows with 50 levels and there is a 100-level version for Android (EUR 1.70 / USD 2.30) and iOS (was it taken down? License drama senses tingling!).
I don't know anything about the availability/license of the build instructions/scripts for the portable platforms and of the additional level files but assume they are closed.
Phlipple is by Remigiusz 'mal1ce' Dybka, who also made Zaz (including a [proprietary?] version for Android).
