Hey all, just shipped a small patched version of Gem Worlds (v0.5.1) with a minor fix. In the tenth level, you are much more likely to get a "good" generated level (with keys far from the lock and the player start position).
While you may still end up appearing close to the keys, which might also be close to the exit, the prevalence of this is much, much less now in the v0.5.1 patch. Enjoy!