There’s a genre of games called “cave fliers” which don’t get a lot of love anymore. You see one now and then, and smartphones have gotten them a little attention again, but they’re not exactly well-represented. In a way this isn’t surprising, cave fliers are characterized by taking something simple, movement, and making it difficult. People can get frustrated when all they’re trying to do is get from here to there and they can’t even manage that much.
Cave fliers are games consisting of moving against gravity, almost always through enclosed spaces and usually by means of a single propulsion mechanism which has to be aimed in order to direct your motion. The most common way this is implemented is something along the lines of Asteroids – you can fire your rocket to move forward, wherever you’re pointed, and you can also rotate, and that’s it. Those are your movement controls. The difficulty is mostly about the strength of gravity and your rocket, and how forgiving the ground is when you run into it. There are often enemies and some element of combat, but that’s not usually the focus. Frequently, just to make to make things harder, there’s also cargo involved – something heavy to be awkwardly transported.
It’s a quirky genre but there are a bunch of recognizable examples, it’s just that almost all of them are 15+ years old: Thrust, Solar Jetman, Sub-Terrania… Lander was a 3D cave flier released in 1999 where you controlled two rotational axis with your mouse instead of just one. That was a good one. Flappy Bird could also be described as a greatly simplified cave flier, though it isn’t the most flattering example.
Hanna in a Choppa is a flash game from 2008 which takes the old model and does away with a lot of the difficulty, while adding some humor and a whole lot of orange. In some respects it could be described as a little dumbed-down, most of what makes it easier is a control scheme that operates in world space: from the perspective of the player rather than from the perspective of the player-character. So up always means up, no matter which direction the PC is facing. This doesn’t make physical sense, but it does make for a light and enjoyable game. The developer agonized a bit over this decision, and wrote an article describing the design process here.
Good news! The classic cave flier control scheme is still available in the options, though it uses a mouse for rotation rather than the more typical keys. That… seems like a mistake for a flash title which takes place in a small box within a browser, but at least it’s there for the hardcore cave flier aficionados. I don’t recommend it.
In 2012 there was a sequel, Hanna in a Choppa 2, which added a bunch of non-choppa vehicles. For some reason this is named “Tunnel Pilot” on addictinggames.com, who sponsored its development.