It loses its footing a bit in the last 2 stages with a weird drop in boss quality and annoying sections (those damn trains), the first 4 stages are impeccable. I could replay Stage 3 50 times in a row without ever getting tired of it. Definitely one of the peaks of arcade action platformers and my personal favourite one.

Any game that lets you play as a pretty girl with glasses and fill a bunch of Nazi aliens with hot lead is pretty good