tModLoader is essentially a mod that provides a way to load your own mods without having to work directly with Terraria's source code itself. This means you can easily make mods that are compatible with other people's mods, save yourself the trouble of having to decompile and recompile Terraria.exe, and escape from having to understand all of the obscure "intricacies" of Terraria's source code. It is made to work for Terraria 1.3+.
Due to rate limiting the console on the panel cannot keep up with the game console and the build will complete before the panel console may show it. Reloading the console will load it to the latest part of the log.