Why do I love seeing game engines having their source code released under free software licenses? Because it means that intrepid coders and passionate enthusiasts of the game can take that code and bring it to a platform it was never released on, or make massive improvements to the engine if they so wish!
In this case, the former has happened to two old DOS first person shooters from Apogee Software (now 3D Realms): Blake Stone: Aliens of Gold and its sequel, Planet Strike!
Both games utilized id Software's Wolfenstein 3D engine, but with some minor enhancements like ceiling and floor textures and primitive variable lighting. The setting for both games is a somewhat pulp-like sci-fi future, with Blake Stone, a decorated veteran of the British Royal Navy turned intelligence agent, out to stop a mad scientist known as Dr. Goldfire from taking over the known universe with an army of genetically engineered mutants and monsters. Unlike Wolf 3D, where progress from floor to floor is linear and one-way, Blake Stone's 6 episodes in Aliens of Gold (and large science facility in Planet Strike) allow for some minor backtracking, meaning that Blake can go back to previously played areas to look for additional bonuses or treasures, or to find secret stages.
But getting back on track, both games had their engine source code finally released in 2013, after long being considered lost, and a few source ports started hitting the scene. In this case, since the original games were DOS only, it's nice that Amiga ports of both games were made!
The source ports for Aliens of Gold and Planet Strike are both available for download on Aminet. According to the READMEs for both games, the requirements are:
- AGA Amiga with a 68030 CPU (40+ MHz recommended)
- 4 MB Fast RAM (2 MB w/o music)
- AHI (v4.18 recommended)
- Game data files for each game (all .BS6 files for Aliens of Gold and .VSI files for Planet Strike, copied to each respective drawer)
I've run both engines on my emulated Amiga 4000 with a 68040 CPU and plenty of Fast RAM, and I've gotta say that the engines themselves run smoothly on this setup. My big quibble is that all of the game's AdLib sounds and music, as well as the digital Sound Blaster effects, have to be converted to work with this port (a tool included does this for you on first launch), but the resulting AdLib sounds and music sound quite off at times (moreso the sounds than the music). The digital sounds are unaffected and sound fine, but it does bother me a bit to hear off-kilter AdLib sounds. But other than that, everything's gravy with these ports, and they're well worth trying out for Amiga users who may have never played these games before!
Do note though that you need to get the data files for the game first, and Aliens of Gold's data files must be downgraded to v2.10R files (again, a tool is included to do this for you!). Both games are available on GOG.com or on 3D Realms' own site.
I've recorded a little runthrough of the first stage of Planet Strike on my setup to show off the engine as well, which is up on my YouTube channel.