In case anyone doesn't know Alien Soldier is awesome.  The entire game is pretty much a boss rush, but it has a large variety of bosses that are all unique.  It's also ahead of its time with the lower difficulty even letting you adjust the speed of the game, so you can slow things down if a boss is giving you issues, to make it easier to dodge attacks.

So despite the fact it's from Treasure who was well known for hardcore action games, it's very accessible to a larger audience if they choose the lower difficulty.

Both Alien Soldier and Light Crusader are contained within the Sega Genesis Classics collection that's on Switch, is this not being counted as a previous release for some reason? Or is this just talking about systems before Switch?

Light Crusader is pretty good as well. In some ways it sort of feels like a sequel to Landstalker with the isometric viewpoint, except it has 8-way movement so the controls are less confusing.