good... but not great
Ok, I usually like to start with the good: the game is solid. Great graphics and visuals, mouse controls [love any game that uses only the mouse], and the game is challenging yet not impossible [unless you set it to impossible, of course :p].
But, well, it's been said before in some reviews: needs a shop or level system or something. Otherwise, it becomes tedious -really- fast. By what I read in previous reviews, you already know this, so I will spare the details and just agree in the fact that it would help the game a lot to have some form of upgrade system or shop.
Other than that, it is a great, solid game. Good job.