Pretty much what I expected, it simply looks like the rest of the engine did. Normally speaking it shouldn't be that bad, but if the cover was loose as you said, it is absolutely no surprise. So, get a new belt and tensioner and what ever tools you need and change it out, cleaning as you go. With a little bit of luck, it'll run fine after that. If you plan to do more mudding, you may want to use blue loctite on the cover screws and probably some RTV for the sealing surfaces as well...
Best of Luck, Bud!!
B