On the PAL version, it's a lot easier to get the enemies into the pit on the bridge on Mission 6, because of the screen scrolling farther to the left. On NTSC, it's still possible to get the enemies into the hole, but you need to stay as far to the left as possible and block their attacks and grab and throw the enemies.

It lags a lot on Mission 4 though, I also noticed the enemies weapons despawning.