I actually have a little sample I wrote called "Looks Level to Me" where I show one approach of going about that. In that sample I also provide a short sample of doing a PacMan level (although the code is commented out). Might be of some help to you.

That's because where you're checking to see if he's hit the ground an resetting the IsJumping variable to false is in a location where it can't ever get hit. You have it within your block of code to make it jump. So it will only check once when he's first jumping and then never again. You need to pull that code out of that ...

This seems like a better thing to ask for in your own blog. I'm going to lock this thread since actual advice on the artwork is being given and refused and the only purpose seems to be to talk about your game and spark discussions about that. That type of thing is much more suited to your own site and whatever forums/blog you have there.

No rewriting is required. There are several XBLA games written using the XNA framework already. The Dishwasher is one of those along with Yo-Ho Kablamo, Blazing Birds, Rocket Riot and Schizoid (there may be others as well, but those game in particular announced the fact). There will be enhancements necessary to meet the strict XBLA requirements ...

Breakpoints do change something important in games. Timing :)  Basically simply by having a breakpoint in your game you can interrupt the timing of when things occur and when you have a game loop running 60 times per second that's a lot of timing you're interrupting. When encountering some type of bug that seems to be timing ...

They actually are changing but it's happening so fast you're not seeing it. Remember that the Update method attempts to fire 60 times per second. So when you press the A key, your code is detecting that press in a millesecond and switching screens which then checks to see if the A key is pressed and switches screens. This happens super ...

This is also the approach I've been taking with the tutorials I write. They might be too basic for you or you might find them useful. But I'm trying to slowly, step by step build up the information you need to make games with over complicating it with making an actual game.

Have you read through my "State of Things" tutorial? It might give you the information you're looking for. I try to explain what "state" is in it's simplest terms and then walk you three ways of doing it from the simplest to the more complex.

Compile and run less often. That's my number one tip for speeding up the development workflow. Too often I found myself, changing something in code and then quickly compiling and running to test it out. Finding something wrong then quickly repeating. By slowing myself down and slowly and carefully thinking through what the change means ...

For me, I think the difference is that I didn't have to learn game development OR C# when I started with XNA. You're attempting to learn all the concepts of programming, then tacking on the concept of game development and then on top of that trying to learn how to use a new framework. I can totally see how that might be a little ...