When you beat the final boss this will get you 500k.
Dont mind when you lose a live (resetting the high score to 0) while playing through the levels 1-6.
It does not matter because finishing the game will net you enough score to get all three Score-Achievements.
Also finishing lvl 4 gives you 100k for the boss.
And finishing lvl 5 gives you 150k for the boss.
When losing a live simply push (LB and then) Start to continue and ignore the score reset.
Make sure to push LB when the "Continue countdown" starts.
Because if your credit count (which can be seen in the lower right of the screen) is 0 you cant continue by phushing start.
To make this a little bit easier you can replenish your Credit Count at the very start of the game to lets say a number of 20-30 by pushing 20 times LB
You can die as often as you like unless you keep an eye on the Credit Count.
When there a too many enemies on the screen you can do a charged attack by keeping the punch button pressed until the power meter on the top left screen is entirely filled blue. Releasing the hitting button will unleash a special attack depending on which orb you picked up last (those round things lying on the bottom throughout the stages with letters A, B, C or D).
Everything else is learning by doing and should be not too hard if you played arcade games like this before.