I've poured about 24 hours of playtime into Luftrausers and I can finally say that the game is very barebones. Sure, the floaty controls and 2D shooting is satisfying, for a few hours that is. There's only 15 parts to customize your aircraft with, 7 enemies to dogfight with, and 1 gamemode: shoot things to get points until you die. It's an endless wave game with some very frustrating elements to it such as the simple art style which is pretty, but can interfere when there's a bunch of similarly colored things on the screen and compounded by immense screen shaking when things explode and stuttering when you take damage. The "100 challenging missions" the game touts is nothing more than a list of basic and boring goals such as "Kill a Blimp" or "Get a score of 8000" that is effectively a list of achievements that quickly becomes a test of luck down the line with its pseudo-difficulty.
The bullet hell nature of the game is also hindered by the fact the camera is heavily focused on your rauser despite all the airspace available, you will often find yourself flying straight into a cloud of bullets that leaves you a very small window of opportunity to dodge whereas other bullet hell games gives you view of the entire field to plan out your maneuvers. All of this and the game asks you for $10, not really expensive, but for that price one could buy other replayable games with truckloads of more content such as Binding of Isaac, Dungeons of Dredmor, FTL, or Risk of Rain. Wait for a sale if you're still thinking about this one.