quite good
I really like this type of game and I can honestly say that this is one of the best i've ever played of this type.
-Graphics are this game's strongest point. Nothing short of brilliant.
-More enemy types would have been nice but it's not a big deal. I found that a fair strategy for defeating them is to stick close to the walls - the AI seems to get stuck against the wall which makes an easy target.
-Upgrade system is nice. Enough variety to experiment with different builds. I do very strongly feel that you should award two skill points per level after level 5 or something like that. One just isn't enough because it starts to get too difficult far too quickly. Another thing that would have been nice would be more weapon types. Missiles are a personal favorite. And a way to get more bombs would be swell as well. Perhaps as random pickups?
But as it is right now I just don't feel it's possible to get fully upgraded in arcade mode. Unless some people here have inuman reflexes or something.
Not much else to say. It's a good game. Could be better but that could be said of any game.