A few things I noticed while reading through the readme:<p>* For me to consider using a PHP library in 2015, it <i>must</i> support Composer.<p>* Currently, a lot of the API is static. This makes it hard to inject the template engine as a helper into some other code. Personally, I would prefer a non-static API.<p>* The template and cache paths seem to be fixed to the location of the library. If this becomes a Composer package, they must be configurable.<p>* From looking at the syntax, how does your library compare to Twig? Sure, the setup process for Twig (initializing the environment, template loader, cache and stuff) is a bit more work, but after that, it's as easy as ``$twig->render('mytemplate.twig', [...data...])``. (Plus, Twig has some nice syntactic sugar, like an else-clause for loops.)<p>* Is there automatic HTML encoding? This is one of the most compelling reasons for me to use a template engine. Whether or not stuff is automatically encoded, this should be mentioned prominently in the readme so that users don't create insecure templates.<p>* On a really completely personal note: I don't like ``.tpl`` as a file extension. It's too generic. It's like naming my PHP class files ``.class`` -- IMO the extension should indicate the file syntax/type, not the file's purpose. Plus if I look at your roadmap, using .tpl might be a problem when you support JavaScript as well.<p>[Edit] I just noticed how negative this all reads. Please take it as constructive cristicism rather than me bashing your work. :)