I liked it quite a bit. Not as good as the best in the genre, but shooters with production quality like this don't come very often nowadays, so it's worth it just for the wow factor even if you don't enjoy the gameplay 100%. You will definitely enjoy unlocking and using all the crazy unlockable ships - some of them have really imaginative weapons. There are also things in the game that I've never seen in the shooter before, such as different variations of the same level on next playthrough depending on the hidden switches you activated on the previous playthrough. For example, if you read up on End boss on level 2 in the in-game enemy library, it will say that the boss has the ability to control the humidity around it. So if you tinker with this end boss in a certain way, it will[/i ]drastically change the humidity and atmosphere on the 2nd level next time you play it! Make sure to read some FAQ on this as you'll be missing out if you never discover those secret levels and level variations. Level layouts could be better, but end boss designs are very nice.
Also, I would say it's the second or third best looking 3D shooter I've ever seen, and looks absolueltely gorgeous (whoever said it looks sub par, what the hell are you smoking, and what other games of this kind look better to you?). The only for sure better looking game of this kind would be Gradius V, and one could argue with pros/cons for Ikaruga.