After a little trouble, all is well - apparently I had to join "stk-team" rather than "launchpad translators". I joined, and am now working on the translation. Thank you Auria!
Now, some questions about the translation itself:
1. In Hebrew, unlike most (maybe all?) languages you have translations for, verbs get inflected by gender. This means that a sentence like "%0 eats too much of %1's cake" should be different when %0 is Tux than when %0 is Suzanne. Right now everything is translated to the male form, which seems very unnatural when an obviously female character (not that there are many of those...) is involved. Is it possible to solve it, hopefully without adding tons of redundant strings to languages that don't need them?
2. This might sound petty, but I can't help but notice - of all the in-game strings, only two (in the English strings) end with a period - "%s is being bounced around." and "'%s' has been eliminated.". I assume this isn't intentional (I can't think of a reason for it), so I assume it would be better to translate without the periods. If it is in fact unintentional, I'd recommend removing them from the English strings as well (if only for strange people like me who notice such things...).
3. In the help and options menus, almost everything is aligned to the left, which doesn't look good in a right-to-left language. It's not very important, just something that might be nice if you have time.
(I guess that's more of a bug report or a feature request, but I didn't see in your contributor's guide how to make those)
4. This is really up to you, but the credits section is not translated - this means Hebrew speakers might not know who you are and what you did
