Here’s a list of other interesting projects.
Frameworks / engines :
Fixel – A free Actionscript (Flash) library.
Construct – A free, DirectX 9 game creator for Windows, designed for 2D games.
SwinGame – A 2D game API.
HTML 5 Canvas – HTML 5 Canvas draft.
Haaf’s Game Engine – Hardware accelerated 2D game engine.
Löve – Free 2D Game Engine.
PTK – 2D Game Engine for Mac os X and Win32.
AGen – 2D Game Engine and Framework.
Torque Game Builder – by Garage Games.
Nimble 2D – A 2D game development blog using VB.Net.
IndieLib – 2d Engine Rapid Game Development.
Slick – 2D Game Library based on LWJGL.
Sawblade Software – Power Game Factory.
Scary Fish – Scary Fish.
Quantum Event Games – Quantum Event Games.
Tile Mapper – Tile Map Editor.
ZweiDe – A 2D C# game programming framework.
SGDK – Scrolling Game Development Kit .
Easy2D – An object oriented game engine that makes possible writing 2D tile-based
games with speed and ease.
Compil Games – Game creator toolkit.
DMedia – multimedia development using the D progamming language.
PhoenixGL – A 2d C++ game engine.
SFML – Simple and Fast Multimedia Library.
PopCap – Games Framework .
Angel engine – A cross-platform 2D game prototyping engine based on OpenGL and C++.
CITRUS Engine – Flash sidescrolling platform game engine built on the power of ActionScript 3.0 and Box2D.
cocos2D – A framework for building 2D games, demos, and other graphical/interactive applications.
SCRUPP – Create your own 2D games and applications.
SMILE – Cross-platform library designed to provide simple API for creating and managing 2D interactive audio-visual projects.
VbGORE – A powerful, open source, and free online RPG engine
SpriteWorld X – A game SDK for Macintosh written in C.
Pixel Art Library – Fast and friendly 2d game library for Common Lisp
TinyLine – 2D implements a mobile 2D graphics engine for J2ME platform (CLDC and CDC).
GameSpaceLib – GameSpaceLib is an open source and very easy to use multimedia library specially designed for game, engine or framework programming in C++.
FlashPunk – FlashPunk is a free ActionScript library designed for developing 2D Flash games.
Ethanon Engine – a free 2D game development tool focused on the recent video cards for hardware acceleration and shader effects.
Adventure Game Studio – allows you to create your own point-and-click adventure games, similar to the early 90′s Sierra and Lucasarts adventures.
Play Basic – a Easy-To-Use programming language, designed for the creation of applications and primarly 2D video games for Windows computers.
djinnengine – a 2D iPhone Engine using OpenGL ES 1.1.
Tempest Game Engine – is an easy-to-use cross-browser web-based game client and server
Pixie – A 2D game engine for C++
BYOND – The premier community for making and playing online multiplayer games.
EffectGames – Effect Games provides free, online tools for building, sharing and playing your own browser based games.
Eclipse – Eclipse is a free to use 2D game engine.
Widelands – An open source real-time strategy game.
OSARE – An Open Source Action Roleplaying Engine.
GOSU – A 2D game development library for the Ruby and C++ programming languages, available for Mac OS X, Windows and Linux.
Spring Engine – A powerful free RTS engine developed for Windows and Linux.
Flixel – A revolution in Flash game production. An amazing new way for man to interface with machine.
Chingu – Make games with Ruby!
OpenTH – A free, open source project aiming to recreate the classic Bullfrog title « Theme Hospital ».
Corsix-TH – Open source clone of Theme Hospital.
OpenTTD – An Open Source clone of Transport Tycoon Deluxe.
Unknown Horizons – A 2D realtime strategy simulation with an emphasis on economy and city building.
Superfrog remake – A remake of Superfrog.
The Legend of Mazzeroth – A 2D Isometric Open-Source MMORPG
Battle for Wesnoth – A free, turn-based tactical strategy game with a high fantasy theme, featuring both single-player, and online/hotseat multiplayer combat.
0 A.D. – A free, cross-platform, under-development, 3D, historically-based, real-time strategy game.
UnderCroft – A great epic adventure in fantasy world full of magic and monsters.
Damnation of the Gods – A Dungeon Master clone with additional features and updated graphics
OpenXCom – Open-source reimplementation of the original X-Com
Knights – A multiplayer action game involving several knights who must run around a dungeon and complete various quests.
Metal Slug sprites
Open Game Art – A community that brings like-minded coders and artists together for the purpose of creating Open Source video games, by providing a human-edited, searchable database of freely-licensed art resources.
Spritelib – A GPL collection of static and animated graphic objects (also commonly known as sprites).