Please, please, PLEASE don’t use installers, they are purely annoying for such a small game, and it keeps people who are using a shared computer (e.g. a library) from playing the game.
BTW, the term “professional” gives the idea of something high-quality, or extremely well-done. Whether or not somehting is “professional” has nothing at all to do with how long someone has worked on something for.
About the game: (I am going to be completely honest here, don’t take it the wrong way.)
In all honesty, this is NOT professional. It might sell, yes, but it is a far, far cry from TRULY professional games. It might be fun, and it might get attention when you call a game professional, and try to sell it, but it DOES NOT MAKE A GAME ANY BETTER.
The game looked somewhat nice, with that radiosity baking, but it needs TEXTURES! Real textures, not lightmaps.
Basically, it needs polish, textures, more exciting-ness, more story, and most importantly, reworked gameplay. The way it is now, the rockets are bland and uninteresting, try livening them up with sound effects, more smoke, flares, etc. The ships are cool, but they also need actual textures. The intro screen just looks, and forgive me for saying this, bad. It is unfocused, not aesthetically pleasing, and certainly not professional-looking. Try using some different colors, or reorganize the whole thing.
Anyway, I hope you take my suggestions as constructive criticism, as they were meant to be. Far too many people can’t take constructive crits in stride, and they become defensive and THEY DON’T TRY TO LEARN from them. The best artists learn from and accept construstive crits, compliments, and even destructive or negative criticism. Just try to figure out why someone doesn’t like something, and then FIX IT, for crying out loud. Don’t let pride stand in the way of you making a better game.
Keep working, and it will turn out well. 