- Yes, there's support for "Dear IMGUI" (see e.g. https://twitter.com/wvo/status/1092948776388485121) and there's also a simple GUI system written entirely in Lobster specifically for game menus/UI and such.
- Speed is still being improved, but in its compile-to-C++ mode it should be a lot closer in performance to C than Python :) It also has a "JIT" mode that goes thru libtcc, but is 3x slower. It's very fast as a game scripting language, but it does not compete with C/C++/Rust as an "engine" language just yet, you are still expected to write the absolutely most performance sensitive functions in C++ (as is the case with a lot of built-in functionality). The language has the potential to compete directly with C++ at some point, but getting there will be a lot of work.