you do need to put in some elbow grease your self though
6. Installation and running
You don't need to install OpenTomb, but you need all classic TR game resources. Problem is, these resources (except level files themselves) are tend to be in some cryptic formats or incompatible across game versions. Because of this, you need to convert some game resources by yourself or get them from somewhere on the Net. Anyway, here is the list of all needed assets and where to get them:
Data folders from each game. Get them from your retail game CDs or Steam/GOG bundles. Just take data folder from each game's folder, and put it into corresponding /data/tr*/ folder.
CD audio tracks. OpenTomb only supports OGG audiotracks for a moment, so you should convert original soundtracks by yourself, or just download whole TR1-5 music package here: http://trep.trlevel.de/opentomb/files/tr_soundtracks_for_opentomb.zip
PLEASE NOTE: script file bundled in this archive is outdated, so don't overwrite existing soundtrack.lua file with one provided in archive.
Loading screens for TR1-3 and TR5. For TR3, get them from pix directory of your installed official game. Just put this pix directory into /data/tr3/ folder. As for other games, it's a bit tricky to get loading screens, as there were no loading screens for PC versions TR1-2, TR4 used level screenshots as loading screens, and TR5 used encrypted format to store all loading graphics. So, to ease your life, you can simply download loading screen package here: http://trep.trlevel.de/temp/loading_screens.zip
Just put it right into OpenTomb directory, and that should do the trick. Note: engine supports png and pcx format of screen images.
On Linux, all I had to do for TR 2-5 was use Innoextract on the GOG installers to get the assets. The original being a DOS game had a slightly more involved process.
I wonder if there's a way to extract the files of Tomb Raider I for Android THEN make it run with this open source engine on PC. Would be neat.
As far as I know, the only version's assets that have been outright stated to be incompatible is the Sega Saturn version. Though the only way to know for sure is to ask on the forum.
I should have also mentioned that there are pre-compiled binaries for Windows users to download, but OSX and GNU+Linux users will have to compile it from source (which is pretty straight forward).