Here is my 100% Achievement guide for Bullet Beat!
Best place to do this is on level 6.
You CAN do this on endless mode but it is slow, and if you end up dying and not getting it, it just takes a while.
Level 6, you quickly get to the boss where we get this done.
The boss is a big red button behind a barricade and throws a ton of enemies at you.
When you shoot the two buttons beside him, the barricade opens up and the enemies stop coming.
You can either, stay in the middle flying around, avoiding the enemies and the big and small block enemies come quickly towards you anyway for easy combo...
OR
What i ended up doing was, stay at the very bottom of the screen BANG ON in the middle of the screen and just keep holding
.
That way, the enemies were ALWAYS coming in towards you, and even if they attach themselves to you, they explode just before the combo goes away, so your constantly getting the combo up without moving!
Either way, hope you get this nice and fast!
Hope This Helps!
Level Timestamps:-
Level 1 - 0:40
Level 2 - 3:50
Level 3 - 7:30
Level 4 - 10:25
Level 5 - 14:55
Level 6 - 18:10
Combo 500 & 1000 Achievements - 20:05Level 7 - 21:30
Level 8.1 - 24:20
Level 8.2 - 26:20
Level 8.3 - 30:00