Completed the game.
The SNK 40th Anniversary Collection was on sale for 119 DKK. This looks like a great emulation package with a lot of games I have never played. 'SAR' was one of them, I have never seen this game before. It's an Ikari Warriors-style multidirectional shooter with a jump/dodge roll. The game features some very elaborate enemy transformations. The most extreme example was:
A mech with a gun that got its head blown off and turned into
a headless mech that blindly walks forward until it explodes and out falls
a human pilot that when he dies, mutates into a big xenomorph, which gets its head half shot off, and then
the maimed xenomorph charges forward until it explodes into a bunch of gross entrails.
Screenshots marked with 🍒 are created by syltefar and are considered public domain, free to use for anything. If you want to, you can note where you found it and link to this page.