New, visible features are of course most exciting, so that's what I'll cover this time as well - sorry devs, we all know you have to do lots of boring work too, but it's not that easy to take screenshots of solved bugs. ;)
The kart selection screen
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What "works":
Everything as far as I've seen. Some of the karts have been revamped, for example Nolok. It looks a lot better; he got a cooler looking kart more in style with his nature. :)
'About'/'Credits' screen
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I was thinking of writing 'What "works:"' here as well when I realized there isn't much to do in here.
Nonetheless, you can lean back and enjoy a nice animation showing if not all, then most of the contributors to STK. The animation is simple but smooth; I've proposed adding an option to stop and/or change back and forth the different "pages". It's on an internal ToDo list, but obviously it's not top priority - if you want to help out with this or anything else, you are very welcome to do so. Just be sure to contact the developers first - preferrably via the mailing list - in order to avoid duplicating work and to get some coordination.
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Note: As the "STK w/Irrlicht" branch is still in a very unstable state, the general public is recommended to use the latest stable version (0.6.1a) of SuperTuxKart.