1990s or earlier anime where mecha are ambushed by collapsing a cliff on them

Question

I'm looking for an animated film I remember watching when I saw a kid, so would have been available by mid-90s on VHS

There are a few details I remember, the main one being that one of the early scenes in the movie several mecha are ambushed by someone firing a missile into a cliff, causing the cliff to collapse and bury the mechas. Although I believe the mecha survive this and kill the ambusher.

Later on, I remember some characters going into space / to a space station, and then a battle around a city on earth again.

Answer 1

Robotech II: The Sentinels? Originally planned as a sequel to Robotech; a few episodes were made before it was cancelled, and put together as a single film that went straight to VHS with limited air play in the late 80's.

The cliff ambush happens early on when the Invid antagonists invade the mostly abandoned home world of the Robotech Masters, themselves the antagonists of the second part of the original series.

Lots of other fighting, and scenes in space as well.