Today is a game engine special on Free Gamer. These are the projects that take your favourite [old school] titles and provide not only a native port but also fix all the nasties that had you saving and loading or even resetting your PC in the past. I remember the days of autoexec.bat and making every byte of that 640k count. Well these won't give you that fun but at least you get to play your old games!
Let's start with the exciting FIFE: Flexible Isometric Fallout-like Engine. Started as an attempt to make a Fallout engine, it is becoming more ambitious and there are even rumours of a FIFE-based game in development. It should be able to run fan-made Fallout mods like the aptly named Fan Made Fallout.
I have a pet favourite among RPG engines - GemRB. (I respect the steady progress on a difficult project.) This Infinity Engine emulator aims to be able to run the Baldur's Gate titles and even improve the experience they offer. The development version is advancing nicely and hopefully the next release will give BG fans something to clamour about even if it still won't be quite capable of playing a full game.
Let's not forget ScummVM, one of the grand daddies of Free Software engines. This enables a host of old-school adventure games to be playable in a modern environment. Since it's inception, some of these adventure games have even been made freely available by their publishers, notably Beneath a Steel Sky and Flight of the Amazon Queen. Sadly they show their age. As fickle as it is, the low resolution makes it harder to enjoy the game when we live in an increasingly detailed and beautiful digital world.
FreeSCI is another adventure game engine for the many old Sierra titles out there. Like ScummVM, it boasts an impressive list of supported games with more added each arbitrary period of time that goes by.
The classic project of the open source RTS engines is Stratagus. Once named FreeCraft, it has survived a blizzard and been made stronger for it. The available games, not counting Warcraft support through Wargus, are still a little rough around the edges but the future looks good.
Speaking of snow stormy games, we come across SCSharp, a C# adaptation of Starcraft. It's not yet capable of much more than loading a few game objects but it's worth watching out for.
Of course no RTS-related round-up is complete without a mention of something C&C (or should I say Dune 2 reincarnate). The main effort here is FreeCNC. Or should I say FreeRA, as it appears FreeCNC development has ceased so somebody has taken on the codebase under another moniker.
We finish with OpenTTD. This has breathed life into an excellent old-school game. Transport Tycoon is addictive and OpenTTD (partially inspired by TTDPatch) fixes the old problems such as vehicle limitations and then adds even more features to the game. However they are still working on the crazy railroads the AI tends to create! They are working on a hires replacement graphics set which will make OpenTTD a game in it's own right, hopefully by the end of the year.
I can only mention so much so left out the various engines ID have open sourced. However, if I missed any other cracking open source engines please comment below!