Don't judge a book by its cover. This little gem is one of the best strategy games I've ever played! I especially love the lack of eye-candy, which in this kind of games is just a distraction.
Many campaign options and modding capabilities extend the game's longevity, and replayability is assured.
Frame rate slows down at times in big cities, but that's not too bothersome.

I wasn't so hooked to a shoot'em up since, like, many years? Keep in mind that I never liked bullet hell shooters, I'm more of a "classic" oldschool shooter fan. And I don't like vertical scrollers with horizontal orientation either. In fact I actually bought this game mainly to support the makers, I thought I'd never play it much.
Was I so wrong!
This game is really something special -- the unlockables keep you coming back for another play; the soundtrack is engrossing and beautiful; the graphic style is wonderful; the gameplay mechanics quite simple; the boss battles are extremely enjoyable.
I even played it with the keyboard before I managed to get hold on my old arcade stick. Keyboard play is feasible, although the Divine difficulty level proves to be unmanageable without an arcade stick. I can fare better with a keyboard than a joypad anyway.
One thing missing is some scanlines graphic options which would improve the visual quality.

Recommended to hardcore oldschool gamers only!
Best platformer I played in the last 15 years (yes you have to go back in time to find something better!).
Level design is brilliant and evil at the same time, but it won't lead to (excessive) frustration, because when you die you immediately respawn without any downtime and you don't have a limited number of lives so essentially you can die hundreds of times. I died 762 times to complete the game!
The soundtrack is so beautiful and together with the graphics brings back so many memories that I bought it as soon as I completed the game: go to http://www.souleye.se/pppppp to buy MP3s or FLACs.