How to back level

How to back level from 50 to 1 - 30 ??

i can't unlock one gun and Explosion light and c4.

you can use some program like ArtMoney
1 start your game ->
2 go to multiplayer ->
3 look your xp on rating board ->
4 alt-tab ->
5 find by armoney your xp (4bit integer) (i think you will find many address. you must repeat 3... 7 step sevaral times and when you will have only 3 adrress go to 8 step)->
6 return to game ->
7 play some time in rating games ->
8 start fight again and change by artmoney your xp during the battle... (decrease xp)

Is memory hacking in Crysis 2 even safe? I would think that the servers would detect a level decrease when it syncs your stats to the server and leave it as it is.

I'm not sure because I play Crysis 2 legitimately and don't use any hacks.