A variety of minor fixes:
- Downgrade shown difficulty for a few levels that were marked misleadingly hard.
- Fix typos in various level descriptions & one incorrect goal art (sandwich police)
- Fix requirements for the 'recursed' achievement.
- Remove esc-to-exit from main menu to prevent accidents.
- Add pointers to certain late-game levels to suggest mousing over for tooltips.
- Hopefully fix font rendering issues.