A handy little "cheat" I found: If the game is running slow during a fight, scroll the screen down so that the game is off screen. You have to be careful about health, but the fight will go quicker. You also have to have auto attack enabled.
Knock Your Blocks Off badge should be rated as impossible. I've removed every block in every level and saved as many extra blocks as I could and I'm still 15 points shy of it.
Should be able to increase combat skills through books. Just make them like 10 times more expensive than the other skills so you can't get to many too early and break the game.
Easy combat skill achievement:
1:Do every side quest you can,
2:equip the best armors you can find (preferably +Learning armors to speed up the process),
3:find a weak enemy,
4:hit defend repeatedly.
1000 points in either weapon defense or magic defense (depending on the enemy's weapon) in under an hour once you start step 4.
Side note: I did step 4 during a campaign quest and it seemed like my skills were going up much faster than during side quests. If this trick doesn't seem to be working then that may be the problem.
 "Arkandian Explorer"){kind=icon}
 "Brick Breaker"){kind=icon}
 "Reactor Mobile"){kind=icon}
 "The King's League Mobile"){kind=icon}
 "PRIOR"){kind=icon}
 "Imperfect Balance 2"){kind=icon}
 "Arkandian Crusade"){kind=icon}
 "Heir"){kind=icon}
 "Genesis"){kind=icon}