Type in during gameplay:
HUIBON          All weapons
VONLUX          Health

Type in at start code menu:
COMMANDO        Access secret level

Level Codes:
                Easy            Normal          Hard
Roman           YPTERFGZ        QJSLVABL        SOIOLGNK
Japanexe        NKTOLVIF        KAYAGEAF        TFJSVJMC
Middle Age      VMXYICCB        MZFSPQDD        XFYAMXIE
Conquistadors   FDQLUGGCC       AVMJFGGU        ZOVASAIV
Wild West       ZREHQFIR        EVBSVTCV        BODSGWLW
Modern Wars     FBTAWPFC        YLHHGXBO        VEJHMQKO
Future          X               ALPYPJFO        ZEYPCEHQ
Beyond Time                     YBULVABN        HMFDLGNN