These are the stage passcodes for the 33 stages (levels).
For solutions see the related question below.
Level 01: 780464
Level 02: 290299
Level 03: 918660
Level 04: 520967
Level 05: 028431
Level 06: 524383
Level 07: 189493
Level 08: 499707
Level 09: 074355
Level 10: 300590
Level 11: 291709
Level 12: 958640
Level 13: 448106
Level 14: 210362
Level 15: 098598
Level 16: 000241
Level 17: 683596
Level 18: 284933
Level 19: 119785
Level 20: 543019
Level 21: 728724
Level 22: 987319
Level 23: 293486
Level 24: 088198
Level 25: 250453
Level 26: 426329
Level 27: 660141
Level 28: 769721
Level 29: 691859
Level 30: 280351
Level 31: 138620
Level 32: 879021
Level 33: 614955
The passcodes let you revisit stages you have already beaten, or if you know them it lets you skip stages that you cannot figure out.
The 33 stage passcodes are:
Level 01: 780464
Level 02: 290299
Level 03: 918660
Level 04: 520967
Level 05: 028431
Level 06: 524383
Level 07: 189493
Level 08: 499707
Level 09: 074355
Level 10: 300590
Level 11: 291709
Level 12: 958640
Level 13: 448106
Level 14: 210362
Level 15: 098598
Level 16: 000241
Level 17: 683596
Level 18: 284933
Level 19: 119785
Level 20: 543019
Level 21: 728724
Level 22: 987319
Level 23: 293486
Level 24: 088198
Level 25: 250453
Level 26: 426329
Level 27: 660141
Level 28: 769721
Level 29: 691859
Level 30: 280351
Level 31: 138620
Level 32: 879021
Level 33: 614955
958640 is stage 12
987319 is stage 22
Number passcodes have to be 4, word passcodes I'm not sure. 13 maybe?
73617
ikillu9
4325345788645890575987695867t85967864364854955985743676797y58hffbvefvbu4765437856585687654.0
51896475
no u must buy them
onkiozza
2nd -90102
Tunes
76869
there is no lvl 30
level 22 is galaga