It is a full game, all the way to the final boss. If you would like extra content, that option is available to you.
Defeat a massive invasion of steampunk-ish enemies in this epic flash game! 25+ levels, multiple bosses and lots of weapon upgrades! After a ton of work, this game is finally out.
For the first time, you can actually buy extra content for this game, and use it on this site.
A full tutorial is in game. Typically you use the mouse to point and shoot. I recommend using the machine gun on lowest tier when starting out. Press 'P' to pause. Hotkeys can be reassigned. Game automatically saves after each level so you can easily come back later.