Lemme get a quick NES game in before Resident Evil 7 arrives (I say from the past). Xexyz was a lesser known NES classic that was really basically The Guardian Legend, except all sidescrolling.
If you haven’t played The Guardian Legend, basically most of the time you go through a bunch of top-down Zelda-ish levels and in between are vertical scrolling shoot-em-up levels with big, crazy boss battles. Again, Xexyz is very similar except all the ground and air levels are side-scrolling instead of top-down.
There are many impressive looking (for their time) bosses and various upgrades and abilities to be collected for your character and his ships.
Also similar to The Guardian Legend though, is the fact that all your upgrades are temporary. You lose them whenever you finish a set of levels or die.
There was also a secret password that would let you skip all the ground areas and do only the boss fights, again, just like The Guardian Legend. The Guardian Legend was a bit longer and nicer looking, but Xexyz still holds up very well on it’s own.