@mike8906 said in Unable to start metal slug 3, 4, 5 rom - Raspberry PI 3, Retropie 4.0.2:

Is it realted to the limitation of the Raspberry Pi3? Or can it be fixed?
I use a memory split of 320 as advised in one of the retropie setup tutorial.
Does the game really requires so much power that it slows down while lots of explosions/enemies appear on the screen?

From the RGUI menu you can "overclock" the NeoGeo. I did that and it works perfectly. I heard that on the original console it lagged too, it's not really the RPi's fault. Still that game is freaking addictive and one of my favorite arcade games.