Fight the Boss of Hourglass Caves. He is easy, and can be defeated in under a minute. Kill him, and get as close to the location he was last at when he died. If you are in the correct location, you will pick up all of the money he spits out.
Duplicating high yield items.
For example, in Stage 1 Level 2 you will encounter two time monsters balancing on clock balls. Each of these balls are high yield items. This means each ball if kept in your sweeper at the end of the round will yield 100 gold. Note: Upon entering the level user should have or obtain at least One Record power-up. After killing off all necessary time monsters, make sure to collect and save both time clock balls remaining behind after killing the time monster atop them. Go somewhere in the level with a fair amount of room and make sure both clock balls are ready to be expelled. Use a Record power-up, and while recording, shoot out/expel both clock balls and wait for Record power-up to run out. After the Record power-up has run out, you are rewound and returned to the state previous to expelling the clock balls. You will notice that your recorded self expels/shoots out two balls. If you now look at your sweeper bag you will see that the two original balls are still there. You can now go and pick up the other two balls and have four instead of two. Even better, if you have two Record power-ups, after collecting the first set of extra balls you can then record yourself expelling all four balls. Then, your recorded self will expel four balls and now after collecting those four, you will have eight balls. Note: This will work with any item.
Unlock a hidden movie of the developers.
Acquire an A+ or better ranking (S+) on stages 1-1 through 8-4 to unlock a hidden Prize that is a short movie of the developers. This video shows up at the bottom of your Prize list under your 'Collection' in the main UI.
Unlock the opening and ending movies
Beat the game to add the opening and ending cinematics to the game to your Prize list under 'Collection' in the main stage select UI