Here are some cheats and tips for the game Quad Challenge.
Level Normal Hard
2 LTR9
3 693F
4 VJSU
5 9F2J TENF
6 13RB ERU7
7 PNF5 DH2F
8 CR11 YZ25
9 5JE8 AGT3
10 8SWG PB4V
11 HGLY
12 Q44E
13 WHCM
14 TVGZ
15 SNDN
16 B16A