Stupid Invaders have the most beautiful 2D graphic I saw. You can barely tell the difference between the cut scene and the game. Objects are drawn in a slightly different manner then the rest of the background so they are easy to see. Sound is great, but lacking a little. Ambient sounds are convincing but too much in the background , so you might think that the game is a little too quiet.
Voices are very good, funny and professionally done.
Unfortunately although the graphics were great, the title of this game is apt. It's not the stuff for younger kids. Basically the only gameplay you can do is move into the areas it allows which come up such as 'move back' 'open door'. Puzzles mainly consist of finding objects or combining objects and using them. You get to play as each of the characters, but being one character doesn't give you advantages over another.