Fun little arcade game reminiscent of some of the classic linear-progressive, 80s-90s shooters: Twin Cobra/Skyshark would be a good analogue, with a fullscreen range of motion for the player ship. Only thing you don't get is keymap options, which seems lazy but is not crippling (WASD or arrows work, and the L, X, and LCTRL keys all autofire the guns).

Achievements are simple enough but not necessarily easy; at first your gun is woefully underpowered and you don't get the chance to pick up powerups that you've missed because they drift off the screen (or into walls). This means it's worth camping in front of a couple of ships very early on until you either die or get a powerup of some kind (3 types: speed, power, stream-angle-multishot). Dying early means you lose nothing but a few seconds; getting to level 2 or 3 with the same nubgun will start to suck and become a waste of time.

I have played only on kb+m but expect that a controller would make this game easier, as they offer full controller support.

Given a price:value rating I'd say full price is a bargain at $1 because 9+ hours ingame = ~$.10 per hour.

Vive la progressive bullet hell and stronk vodka game - Well done NukGames!

[edit]
The dev is active in the forums and responsive to player commentary, as well as game updates to address early player requests.

Finally, I have written a very helpful guide: http://steamcommunity.com/sharedfiles/filedetails/?id=852791481