Pretty EASY Level experience grinding
I played the game through and got to level 41. I had most of the rules and artwork. I did the following:
1] Set rules to GLIDE TIME
2] Set Artwork to STEEL BODY and SHARPER BULLET
3] Play 1-0 (Bad Day at the Office)
4] Pick up the first gun (Shutter MK8)
5] Aim slightly high at all enemies and then lower to be sure at get all +30 headshots. Do not worry about mindjack or stomping as this slows you down.
6] After the first checkpoint you should have about 200 experience points
7] Enter into the second area and do the same, getting ammo as you proceed
8] After clearing the recpetion area, proceed up the stairs and kill the remaining ememies. Remember the headshots.
9] You should get about 650 experience points.
10] Run to exit to save progress
**That is a total of about 850 experience points in about 4-5 minutes***
I took me about 2.5 playthroughs like this for a level up.