It is possible to unlock all skill to level 15, editing DefaultLevelChart.ini located 
in APgame\Config. Open the .ini with any text only editor and rewrite all the level 
cap to 15: SkillCap=15,SpecialSkillCap=15

After this you will still see the level 10 limitation in the character screen, but the 
game will accept the value.

After gainer your first level in the interrogatory room edit your save with any hex editor, 
Documents\Alpha Protocol\Checkpoints:

SKILL_PRIMARY_STEALTH_Level 000000 0F 0000001C. The 0F is 15 in hex, this value is always
in the same position for every skill in the game both active and passive, leave the last 
value, 1C in this case, alone.

SKILL_PRIMARY_PISTOLS_Level 00000000 0F 00000019. remember that only primary skill reach
15 both specialized and not, all the others have lower limit:

SKILL_PASSIVE_PISTOL_RAPID_RELOAD_Level 00000000 01 0000002A. in this case the max value 
is 1 (01). Critical hit has always max of 4 (04).

Check the limit of every value and write directly in the save, Backup first!

When open the character screen the game will ask to save the change even if you haven't 
touch anything, ALWAYS SAY NO! Or the value will return to normal, 15 for specialized 
skill, 10 for all the others.

If the save got edited before having done the .ini change, the value will return normal 
at game start.