luy - There are a lot of games with infinite score bugs. Gemant is the guy who would know the best. He spent years translating the Oriental World Records/Gamest.
Congratulations on your score.
Infinite leeching (infinite pattern application) is possible. If I remember well, this is possible on last Boss (i not remember if at the end of first loop or the second, or both). However you can destroy little enemies that this Boss made because there is a infinite time.
extra:
In japanese version you can obtain 60.000+60.000 pts+ because there is a secret boss character