Typo in ending credits

Issue description

When I launch the rocket, at the end of the credits, it says "... ok, now you can go back and finish flattenning of the entire island."

Expected behavior

This is a typo, it should be "flattening".

(I might also suggest "flattening the entire island" instead of "Flattening of the entire island" too while you're at it).

Reproduction steps

1. Launch a rocket, view credits.

Game version

v0.4.8

Thanks for your report. This should now be fixed in previous version.