I bought some art for my previous game and if I dare say, it looks pretty good:

However with this next game, it requires a lot more art. Too much to "buy", because it would be expensive. Even making all the art in a high quality myself would be extremely time consuming when I am more than just an artist, I am doing jack-of-all-trades work.

Here is the result:

Do you want people to comment on it?

Do you want people to comment on it?

Go ahead.

Also, in case I wasn't clear..... I made the art in the second picture.

You are free to comment on the pictures, or answer my "quantity over quality" dilemma question.

Simply put, the first screenshot looks like it comes from a game I would pay money for, the second one doesn't.

I think if you can't find the money/time to make your assets look acceptable in a project, you need to consider going a different route because honestly it drags the whole thing down. Two ways of doing that are by limiting yourself to existing royalty free art or cutting down the number of assets you need to a level where you can afford to buy them or polish them yourself. You could always try to find a useable easy style (ala South Park or the like). It doesn't matter so much if you're just doing this to practice, but if you're going to try to put it on the market it really matters.

While I do not have any direct experience with selling games, from a small business perspective I would go ahead and purchase the nice assets. Although it may get ridiculously expensive, all good business starts with risk. You WILL NOT sell your game in any significant quantity with that kind of MS-Paint-looking shit on the screen. If you are looking to make money and are using that content, just go get a job at McDonald's; it will pay you more for your time. I would wager that if you have your marketing and distribution plan down and its good (even for an app you should make a full business plan) you stand a VERY good chance of earning your money back and even making a profit. When I used to actually play computer/video games I would play the ones with good art hundreds of hours past beating every single quest and just being immersed in the excellent art assets occupied my time enough for me to be contented.

I don't think your current approach will work. Perhaps get an artist to create something a bit kitset style, e.g. http://www.southparkstudios.com/avatar

Then you can create a bunch of assets based on common nice artwork.

Thanks for the insight everyone. I know now what I must do...

Hold off the cow platformer I was working on (in picture 2) and further develop my space game (in picture 1).

Though the background is really nice on the first picture, I would also get a better font and think about where to place those numbers. The stars could also be better.

There's isn't much wrong with your second screenshot. If you look at a lot of mobile games, you'll see that many of the games have a very simple art style. If you think it will take too long to make your game look better, then find someone else to make your artwork. I guarantee you the person you paid to do the first one spent some time on that. So it's not a matter of quality versus quantity; rather, it's a question of how much effort you are willing to put into your game.

If you can spend hours on coding, definitely spend hours on art, and hours on music, and hours on sound effects, because when someone plays your game, he or she is going to see and hear all of that stuff and not your coding (although bugs and glitches are fairly noticable). I absolutely love games with beautiful music (Legend of Zelda) and I am ashamed to say I would not play a game that does not have nice artwork.

Don't give up on trying to do it yourself. I can see that you're on the right track. The only thing that's preventing you from making greater art is you. Best wishes!

To be honest, I don't really like the first picture. The space background is pretty, but beyond that I really can't tell what's going on in the image--that background is eating everything in front of it.

I'd suggest using a simplistic, highly-stylized art style--and sticking to it. You want people to think "art style" rather than "wow, lazy MSPaint graphics," and deviating from such an art style with even a single asset has a tendency to tip people's perception toward the latter, IMO. For instance, I like the rectangular cows. Combined with the rounded edges on the anthropomorphic sneaker-wearing one, the ellipse UFO, and the relatively smoothly blended ground textures, however, it's not... cohesive. If they were all rectangular or all rounded, and either all textured or all flat, I think it'd look a lot better.