RKA2 doesn't really reach the highs of the previous two Rocket Knight games, but it's still pretty good. The main things dragging it down are weaker presentation, lower budget and unlocking the actual ending behind hard mode. Sparkster on SNES does a similar thing there, but I think it manages to conclude satisfyingly enough on normal difficulty, whereas here it just features a screen that says "End" on it.

There are also some parts of the gameplay that are just kinda rough. The mech stage is really bad and just reuses the boss battle from the cold open, which is probably the clearest point where you can tell they weren't given as much money this time. There are also collectibles in most stages that you need for the true ending, and they're typically in somewhat annoying to reach locations a la the early Sonic installments on the Master System. The other two Rocket Knight games don't have anything of the sort, and I think it's better off that way.

Whatever the case, this is still a good game. I wouldn't play or recommend it before the original game or SNES Sparkster, but it's good. At the very least, the mech fight at the start definitely triumphs over the one on SNES towards the end of the game. That game is my favorite of the three but that part is so fucking bad.