As I am not a professional Game Designer, I feel I cannot give you feedback relevant to actual directions you should be heading for.
Yet I can give you some advice.

Design Games.
I know, its kind of an obvious one, yet its overlooked quite a lot. People graduate from game design courses, and think that's it, I'm done. Now all I have to do is get into the industry and start professional.
I disagree.
Game Design is, at its most basic form, the creation of a game through ones imagination and techniques. How does one improve such things? Buy designing games.

This is how I'd go.
First, organise different genre's of games with difficulty of implementation.
Once this is done, go with the easiest genre and think up an idea. Once you have that idea, design it.
By yourself, design this entire game and how it would be implemented. Include in everything you can possibly think of, and then some.
Now, you have a finished Game Design document right there, just waiting to be created.

Put it aside.

Don't continue to edit it, your not making a masterpeice, that won't help you design games. Now think up another idea of this genre, and repeat the process.
Keep doing this until you believe that you have the competency to design a game for that genre without respite.

Now move onto the next genre.

Are you seeing where I'm going with this? This is actually something I'm doing right now, since it'll help me exponentially in being able to design games. You can even put this in your resume, with link to each and every game design document (or the ones you feel are worthy).
in fact, this would help a lot when you get reviewed. You see, there a lot of people who wish to get into Game Designing professionally, but not many make it. There just aren't enough spots. So when they pick up your file, and look through it, they aren't looking for the credentials you have. Rather, they're looking for what sets you apart from everyone else.
Displaying this in your resume would show them that your committed to your work, that you can think for yourself, that you really do try to improve yourself. It shows that you look critically at yourself, or put in the effort to get someone else to look critically at you, and work from that.

This is only one example, though. You really need to start thinking critically.
What this helps you with is the creation and implementation of a design document of all genres, and also the expansion of idea's through imagination.
What else do you need in Game Design? Think of other methods to help you achieve this. The Game Designer that gets the career is the Game Designer that constantly aims to improve oneself.
---
Am I helping you here? I'm not good with explanations, so I'm never sure if I'm getting my points across to people.
Well, if you have any problems or questions, then post it here or send me a message.

EDIT: oh yeah. In my opinion, creative writing has a huge impact on game designing, whether its a story-aimed game or not. I'd recommend at some point you go back to uni and take some form of Masters in Creative Writing. It'll only go for 1 and a half years full time (or 3 part time), but I think you have to pay upfront. In the course I've been looking at, it is $9000 per Semester.
I feel it is worth it, but as I said this is my opinion. If you consider it, research it and find other people's thoughts on it.

There's lots of good advice here already, so I'll give you the "real talk" shtuff you asked for about your work.

I'm going to be fairly critical, but I'm just trying to help, so please don't hate me.

I'm gonna go from what I think is your worst work to the best.

Skyrim level - If I were looking for a level designer, this doesn't show me that you can do it. If you had a better lit walk-through of the level with the enemies being non-hostile or something so that way I could see the lay-out and design, then maybe it would help. Also, its in an existing games level maker, using all pre-made content, so it won't be considered as strong of a portfolio piece as original content.

Maya models - There are a lot of very skilled 3D modelers, riggers, and animators out there. That being said, I don't think model making is your strong suit. If it is a direction that you want to pursue, then I would try to find an area of 3D content that you want to focus on. Like if you want to animate characters, I would start with simple skeletal rigs and animate out scenes. If you want to do character modeling, start with lower poly characters to learn good topography and patch modeling and practice. If it's just a side note, then I wouldn't nesicarily have this in the portfolio.

The Skyrim level and the Maya models are your weakest because they aren't what you'd expect to see from someone who is going to college for media or game design. I would focus more on original content that is more polished.

Joyride - Its a really fun and interesting idea, but the video is half fluff and the rest is maybe screen shots? Also, the graphics are less polished than the rest, making it kind of rough for a portfolio. You might not have anything to do with the graphics, but that just means you need to get on the case of whomever is so you can have something prettier to show. If you're the designer, that means you have to bring the hammer down and get the art work all on the same page and up to a standard. One thing I would probably do with this game is take it out of the portfolio for now until it gets some more polish and from your resume it seems that it is still an on-going project.

Pyroclast - Another interesting game idea with "meh" graphics. One thing I think would have been great to see here was a video like everything else. The reason I bring up graphics again is because even if you aren't in charge of them, those graphics are what represent your game and ultimately tell the quality of the work done on it to potential employers. You might have done a phenomenal job on your part of the game, but if everyone sees bad art, they'll think the entire game is unpolished.

Massteroid - This one is pretty well polished and has some awards attached to it which easily makes it the piece you want to showcase. I think you even did a good job on the video by having straight up game play, and also with the write up by really explaining what you did, some challenges you faced, and how you over-came them. Maybe adding some links to external sites that have your game listed as winners of those awards will help?

Anyway, my over-all impressions of your portfolio is that you're not really showing what you want to show. From your headline, you say that you're a level and content designer. What you're showing is a couple of space shooters with mediocre to decent looks, an incomplete (but cool idea) racing game with inconsistencies in design, and some pretty beginner level stuff in Maya and Skyrim.

Also, show more stuff! Your portfolio is pretty short on content, so try to fill 'er up!

If you want to help show you're a level designer, I would create some top-down maps of dungeons or levels for a game, then have a fly-through of the level. Also, show some completed game design documents to show that you have the design skills to complete one that makes sense. And finally, I know I've said it a couple of times, but I strongly suggest you get some polish on those games. As a content designer, you need to hold not only yourself but your entire team to a standard. If they can't create content that meets your requirements, then encourage them to practice, do multiple iterations of the content, and if you still can't squeeze what you want from them, then maybe pass the art reins over to someone else. There may be butt-pains flying around, but not everyone is an artist just the same as not everyone is a programmer. Just don't pander to others delusions or whining. Ultimately it is your career and the game that you need to look out for, and if someone can't cut it, than it isn't good for you or the game.

I hope I was some help and that I didn't get you mad. I think you've got some good stuff on there, just not quite enough or quite right to show that you are a level and content designer. It feels fairly unfocused on what position you're looking to fulfill.

tl;dr - your skills are being represented by sub-par art and you aren't showing what you want to show for level and content design. add more content will help.