The 1.0.2 update is in the beta branch. Moving it to default after some testing.
- Force submitting of achievements when entering main menu
- Submitting achievements multiple times by default to make sure the unlock on Steam
- Performance optimizations (these might help slower machines even though the game isn't very demanding to start with)
If you're having trouble with achievements unlocking on Steam, try this now! Let us know if this solves the achievement problems a couple of users have had.