In that same ballpark as Lunar Lander
Don't get me wrong, Lunar Lander
had its own little sidescrolling fine tuning of a lunar module landing type gameplay, unique and so simple, while Chopper Commando is a 2D sidescroller shooter, but the graphical style, sparse and edgy, is so similar in both. That's why I'd recommend these 2 games to be played side by side, because sometimes you just have to do away with games that are more diverse and messier, with lots of graphical elements. There's also another common denominator between the two games, which is the fiddly way in which you maintain your airships in flight. Yap, in Chopper Commando you have to keep bashing buttons to keep your chopper level in mid air, it doesn't control itself, automatically. So that's going to take some getting used to, but the challenge, the combination of maintaining your direction while shooting at things is going to draw you in, making this an all consuming, but ultimately relaxing experience. Try it out, it's a pure arcade oldie, which never goes out of style.