That game generator is great:

"A puzzle game where you wage war on hell because aliens."

Haha that almost describes Disgaea.

On the simple end of the spectrum, I know several people who are always looking for new mini games to add to their social gaming websites. Mostly that kind of thing is clones of tetris, frozen bubble, bejeweled, solitaire (with cards, mahjongg tiles, or pegs/marbles), snake game, asteroids, galaga, missile command, pinball, hangman, shooting gallery (this is based on an amusement park thing not a famous old game). So if you want people to reuse your code, code for these is in consistent demand.

Me, I've got ideas I'd give away but they're all bigger and more complicated. The simpler end of my spectrum would be farming sims and animal breeding sims, tactical combat RPGs, adventure games, and dating sims.

How about a Tower Defense game? The challenge would be to add some elements that are not found in similar games.

elements like what ?

Well, if I knew that, I would make a TD myself since I love these types of games. I suggest playing couple of games here http://turretdefensegames.com and see what you like and how you could improve it. Makes for an interesting study in my opinion. Squidi's Three Hundred Mechanics has also some very interesting ideas. As for that game generator, I didn't find it that great, and I tried dozens of combinations.

Go on GOG.com, purchase Master of Magic, Alpha Centaurai, Master of Orion 1 + 2 - play the heck out of them. They're on sale right now, so buy them, get inspiration and see how great a 2D game can be!

I spent my childhood playing those games, man. I even still play MOO2 from time to time. So, yeah, I know how great 2d games can be :)

And btw, I decided to go with Art Whiz suggestion for a tower defense game. Every few days I will try to post here my progress.

In advance, Merry XMAS :)

If you want a tower defense example, I recommend Plants vs. Zombies if you haven't played it yet. (I mean the singleplayer version, I think they came out with a facebook version recently but I haven't tried that.)

I spent my childhood playing those games, man. I even still play MOO2 from time to time. So, yeah, I know how great 2d games can be

And btw, I decided to go with Art Whiz suggestion for a tower defense game. Every few days I will try to post here my progress.

In advance, Merry XMAS

MOO2 is also one of my favorite games which I enjoy getting into from time to time. Along with Diablo 2 and Fallout 2; awesome games. Glad to hear you're going for the tower defense. Feel free to use the TD graphics from my website, should you want to get a quick start. You'll end up with something like this:

They're free to use and I'll probably add more assets. Merry Christmas to you too and see you next year! ;)

OK, some update on the topic: i did some work on the tower defense game but far less than i intended.
and i need help for implementing proper and smart unit movement(pathfinding). i read this, and this plus some chapters from a books for AI development, but i couldn't come up with any proper code. so if anyone can help me with pseudo code or something on the topic (especially points of visibility pattern) please help :)

ps: i know this is not the proper section of the forum for asking this, but i do not like to open another unnecessary post

You will need to open another new thread, since you are asking a programming question and this is the Game Design forum. Closed.