X-Blades

I started to do the 'Entrance to the Castle' method during a lunch break to start some of the grinding and managed approximatly 900 kills in 20 minutes, (2,700 per hour and I think I am being generous), maybe I wasn't in the most effective place, but I found it quite difficult to get any sort of rythym going.

Then I remembered reading a solution on a PS3 site, so I thought I would give it a go.

Start a game on easy, run to the first rage crystal, kill all the monsters, then shoot all the flying monsters. Next the game will ask you to bind the earthquake spell, do so, but do not use it. I wedged myself to the side of one of the breakable vases to prevent walking forward then entered the unlimited everything cheat, (, , , , , , , ), made sure my shooting was fully upgraded and on rapid fire (). Then faced the rage crystal taped down the and walked away.

With this method I went from 1,789 to 10,000 kills in under 90 minutes, quicker to set up than other methods and you don't need to adjust anything unless your controller runs out of juice or one very lucky monster knocks you off target!

If you need to know your total kills so far just finish any level and the stats screen shows you the total kills you have.

The best way i found to do this was on the level called entrance to the castle. In this area you fight a lot of ghosts spawning out of 2 red orbs. Destroy one and then go to the other but stay back by the columns not to activate the smoke door blocking you into the section. Turn on rapid fire for your guns which is down on the d-pad and aim it at the orb. Just hold in the R trigger and you should be able to kill the ghost as they come out of the orb and just keep killing. I found that you get about 400 playing the hall of columns(and requires a lot more work) but i got about 900 in the same amount of time doing this.

Heres what I did from memory. I beat the game 1st. Then went replayed it. Went to the last bosses room then turned around and went back to the last stage with all the monsters. I killed the waves until the large monster with the shell on its back spawned. Hard to explain but you jump on his back and move around a little so the large monster starts doing circles while you stay 'floating' above him without needing to move. I put it on wideshot and with right stick faced down with a slight spin and held down the trigger to shoot. With this way I could get this achievement without having to even play the game, I set up my controller with rubber bands. Just check back every 30mins because the xbox pauses it for you then.

edit: to see how many monsters you've killed currently. Simply finish any level and at the stats screen it'll tell you the total. When I completed the game I had around 4500 total kills. So doing my above solution it took a few hours to get 10k kills. I would watch TV and while the xbox was in picture in picture so I can check when it goes idle.

First things first. The Kills count from all your playthroughs.
Okay to the farmmethod. After the level "Entrance to the Castle" will come a infinite spawn of small "Dinos" go up the stairs and wait there for them. Look the stairs a liitle bit down to kill them before they com up the stairs.....