The art is okay at best, over all the game feels to slow for it's own good and due to the lack of an indication of wounding your opponents it feels like they are invincible which makes the gun useless.
If you were to ever revisit this I advice giving the enemies an indication that they are being hurt if you can hurt them, if you cannot hurt enemies except for charging your gauge then take away the gun and make the focus of the game running and hiding rather than just being in a single room, and increase the over all speed of everything from player movement to bullet movement.
Overall this is a bad game, but in time perhaps your group could put out something great!