Post your -find text here and we'll see what went wrong.
This is what I used: upright, 8-way, 6 buttons or less, fighter, playable are the only check boxes set.
copy-n-paste these into your -find line. make sure the spacing is still there between all the | and & 's
(buttons=6 | buttons=5 | buttons=4 | buttons=3 | buttons=2 | buttons=1 | buttons=0 | !buttons=) & (joy8way | !'control type=') & !(joy2way | joy4way | 49-way | triggerstick | top-fire | rotary
| doublejoy8way | dial | trackball | pedal | lightgun | 'analog stick') & !emulation=preliminary & (fighter) & !('ball & paddle' | 'BIOS' | breakout | casino | climbing | driving | maze | minigames
| mature | misc. | multiplay | pinball | platform | puzzle | quiz | rhythm | shooter | sports | tabletop | wrestling)
and I ended up with 653 games, including all the mortal kombats.
I switch the genre over to sports and I'm seeing 2on2 open ice and NBA jams, I got 303 games total.
Maybe you've restricted region to USA only? That can make a severe reduction in games.
edit: whoa, sorry about the width of the thread now!