There are still many asserts in the engine. Most of them are irrelevant and should be removed, but while it's not done, the asserts will effectively kill the engine when triggered in the Debug build. Use Release or RelWithDebInfo build if you intend to play (automatically set as RelWithDebInfo in the build scripts).
To build Serious Engine 1, you'll need Visual Studio 2013 or 2015, Professional or Community edition ( https://www.visualstudio.com/post-download-vs?sku=community ).
Once you've installed Visual Studio and (optionally) DirectX8 SDK, you can build the engine solution (`/Sources/All.sln`). Press F7 or Build -> Build solution. The libraries and executables will be put into `\Bin\` directory (or `\Bin\Debug\` if you are using the Debug configuration).
Alternatively, you can simply copy the whole content of the Windows install as base dir, add the `SE1_10.gro` from the repo in the root folder of the install, and then copy the binary built in `Bin` folder
Note that the CD version of SS:TSE used MP3 for music. You will need to build / get `libamp11lib.so` and copy it inside `Bin` with the other libs to have music. Steam version uses ogg and doesn't need this library.
DirectX support is disabled by default. If you need DirectX support you'll have to download DirectX8 SDK (headers & libraries) ( http://files.seriouszone.com/download.php?fileid=759 or https://www.microsoft.com/en-us/download/details.aspx?id=6812 ) and then enable the SE1_D3D switch for all projects in the solution (Project properties -> Configuration properties -> C/C++ -> Preprocessor -> Preprocessor definitions -> Add "SE1_D3D" for both Debug and Release builds). You will also need to make sure the DirectX8 headers and libraries are located in the following folders (make the folder structure if it's not existing yet):
MP3 playback is disabled by default. If you need this feature, you will have to copy amp11lib.dll to the '\Bin\' directory (and '\Bin\Debug\' for MP3 support in debug mode). The amp11lib.dll is distributed with older versions of Serious Sam: The First Encounter.
3D Exploration support is disabled in the open source version of Serious Engine 1 due to copyright issues. In case if you need to create new models you will have to either use editing tools from any of the original games, or write your own code for 3D object import/export.
IFeel support is disabled in the open source version of Serious Engine 1 due to copyright issues. In case if you need IFeel support you will have to copy IFC22.dll and ImmWrapper.dll from the original game into the `\Bin\` folder.
This version of the engine comes with a set of resources (`\SE1_10.GRO`) that allow you to freely use the engine without any additional resources required. However if you want to open or modify levels from Serious Sam Classic: The First Encounter or The Second Encounter (including most user-made levels), you will have to copy the game's resources (.GRO files) into the engine folder. You can buy the original games on Steam, as a part of a bundle with Serious Sam Revolution ( http://store.steampowered.com/app/227780 )