Deep Down is a game that has you try to beat your own best score by making this little yellow square with a face jump down onto various platforms and try to avoid death. Gameplay wise you just have to tap on the screen to have your little square jump.
There's no other controls than that, so it's a very simple game. You just have to compete against your own high score and try to get the gold coins as you drop down, while avoiding all the spikes so you don't die. That's pretty much it for this game.
Visually the game is pixel art style and looks pretty basic, but it serves its purpose as a simple game. Don't expect intense graphics with this one. Overall I'd say that Deep Down is an average game with average graphics.
With very little competition except against yourself, and very little incentives in terms of rewards available to you, I don't see this as being any more than a light time killer that you may forget about pretty quickly. I will not continue playing this game in the future.