This game is be no means great, but it's certainly not horrible.
There are only five levels in this very short game. You control Tails on rails through the air evading hazards and shooting down enemies with your ring. Tails' stamina will decrease through out the level, to replenish it you have to pick up mint sweets in your path.
This game is far from easy. There are many obstacles that you must dodge. If you hit a wall, the ceiling or the floor, you die. There are dozens of enemies on screen to keep you on your toes. When enemy projectiles hit you, Tails will begin to fall to the floor. Just tap one of the buttons and you'll soon resume flight. However getting hit will reduce Tails' stamina bar.
At the end of each stage (apart from the Training Area) you must face a boss. All you have to do is hit them with your ring several times whilst evading their attacks and avoiding the floor or ceiling. This can be quite hard.
The game is hard and took me a few attempts before I could complete it without using Gems Collection's quick save feature. But it's difficulty isn't what prevents the game getting a higher score. It's the fact that it gets boring very easily. I've played worse, but there's almost no variety here making the game extremely shallow. However overall I mildly enjoyed it and can safely say I think it's "an okay game"
Graphically the environments are very bold and colourful. Overall this looks quite nice. The areas look very cartoony in style. The music is just bland in my opinion. The tracks are also very short, so get repetitive.
In conclusion, yes Tails Sky Patrol has plenty of room for improvement and suffers from being extremely shallow. But it is in no way shape or form as bad as people make it out to be, Overall its' okay. I found it mildly entertaining. You can play it on Sonic Gems Collection or Adventure DX, so if you don't like it, those games will have other things to keep you occupied.