Games difficulty level increase over time?

[Hitesh]

With most arcade games, my high scores improve the more i play the game.

But not with....... Mr. Do!
I recently started playing this. Sort of brand new Mame install with all CFG and INI files deleted.
When I started playing it. I used to see the "diamond" around every other game and was hitting (bad score alert) around 175k most times.
Now I hardly ever see the diamond and am finding it tough going by the time I hit 100k and seem to reach 125k max.

Is it me or has the game ramped up the difficulty over time/plays

Hope that makes sense...

 

[Lastspaceship]

I always find robotron is easier the first time I play it in a while..