I've been clicking for a long time now, I first started with k&p here are some tips and things that I find make a good game.

Graphix Vs. Gameplay
A good game has good graphics and good gameplay. True? Well not all good games have to. Some games can live without one of these but if you have none, then your game crumbles. I can usually stand if somebody has 1 or 2 lib graphics but if your game is all libs, your a dead man.

I have noticed people can do amazing things just using the built-in movements. Not everything has to be custom! Take Battle Mek 2.I thought that was a great game, and all it used was 8 direction movement.

Tell me something I don't know
Ok then, to me gameplay is quite important. When I review a game I like to look for originallity. A player will play a game alot if there is good replay value, you could make a really awsome platform adventure. When you're done what's there to do? Not much... So sometimes what your game needs are unlockables.

Replay Value
Easter eggs, Unlockables and cheats. These are some things that make people play your game more.

Maybe include a map creator aswell, I think most puzzle games should have a map creator. Alot of grid based games do well with them. They get those few more stars in the lastability section.

Easter eggs - These are unexpected surprises. eg. you click in the top right corner in the help and it goes "HEY IM THE TOP RIGHT CORNER MWHAAHAHHA"

Unlockables - These are things that a player gains after beating a high score, finishing the game, playing for a long time. They can be things like, new players and more weapons.

Cheats - You know what these are. You should probabley give them out once the game has been finished.

Things to remember
Graphics, Gameplay, Goodies

If you have one of them, your game will go ok.*
If you have 2/3 of them, your game will get some good reviews.*
If you have 3/3 of them, your game will rock hard!*

*May not actually happen, these statistics are a educated guess

Hope your games go well

-Andy (12, Ccsoft)