I was always fond of UFOMania 1, and now I've finally found this.
I gotta say, the neon look was quite good, it gives it that sort of retro "asteriods" feel to it which works quite well. The introduction of the rotating planets was also a pretty neat idea, and is something that could be expanded on if you decide to make a UFOMania 3.
I also quite liked the new obstacles and the variety of planetary defences. They added a new twist, and I had to seriously rethink my strategy for some of the planets. If you keep your players on their toes, you're doing well as a game designer.
The only thing I think could help improve this game is a storyline. We know that these humans are being moved, but we don't know why. Perhaps there is a war going on? Maybe in UFOMania 3, you could have to fight enemy ships to get to the planet, or you could, while saving the majority of the humans, have to try and purposefully kill a specific few humans, who are marked out by being a different colour, say if the humans are usually yellow, there are red ones that you have to kill, for example. It's just a suggestion, I mean, you already have a good and pretty addictive game as it is.
Keep up the good work. :)