CODE  KEY IN . . .                      EFFECT . . .
1     AEUOLTPA                          Infinite lives
2     PEUPPTLA + PLVOLTLL               Start with 1 life
3     TEUPPTLA + TLVOLTLL               Start with 6 lives
4     PEUPPTLE + PLVOLTLU               Start with 9 lives
5     SXUPZGVG                          Freeze timer
6     NNXOYGEK                          Slow down timer
7     AVXOYGEG                          Speed up timer
8     AEUOVIGA                          Start with and keep laser missiles
9     OXUONISX                          Autofire
10    XZEAUOOZ + PAEAKPAA + VAEASPSA    Start on world 2
11    XZEAUOOZ + ZAEAKPAA + VAEASPSA    Start on world 3
12    XZEAUOOZ + LAEAKPAA + VAEASPSA    Start on world 4
13    XZEAUOOZ + GAEAKPAA + VAEASPSA    Start on world 5
14    XZEAUOOZ + IAEAKPAA + VAEASPSA    Start on world 6
15    XZEAUOOZ + TAEAKPAA + VAEASPSA    Start on world 7