I with Kevsoft are had a big work over engine, and now we are have completely new physics to replace Box2d which doesn't fits into platform game-play. New physics provides almost same SMBX physics (values of accelerations and speeds are gotten from SMBX through bunch of a tricks with LunaLUA). With a new physical engine game works faster in 3-4 times faster than was in Box2d. Also new version is going with lua subsystem which provides powerful customization of everything: basic atmosphere, print misc. texts or some debug information, and later will be used to implement NPC algorithms and game-play events required to game work.
This is an experimental version of engine with a new physics which can be used for a preview and tests reasons. You can use it to test any levels or episodes or check out for a new physics system before engine will have finished work with a physics and I will do a creation of NPC Algorithms and layers/events system to have completed implementation of SMBX64 standard gameplay which giving full support of SMBX-based levels, episodes and games.
Important notes! (Read it before use new engine!)