Hi Arrow! Thanks for taking the time to apply for the team, it's awesome that people are still interested in helping us out even today.
We've discussed your application internally, but unfortunately feel you wouldn't be the best fit for the team at this time. Most of the levels left to be completed for GE:S are actually outdoor or mixed environment maps, such as surface and statue park, so your existing experience with indoor work does not cover the full gamut of what we're looking for.
In addition, the work you've put forth shows a level of familiarity with the tools, but as all of the areas shown in the screenshots just use the basic portal aesthetic there's nothing that really shows off your ability to innovate or design interesting but cohesive environments. That isn't to say you don't have this ability, just that we feel it has not been demonstrated.
If you're still interested in making content for GE:S, I would say that it's not a bad idea to come up with some interesting ideas for community maps and make a few of those. This would give you a chance to build up your skills and also give you some much stronger portfolio pieces if you decide to apply for the team again. I would say some immediate goals to work towards would be to learn how to make your own textures, and to design some unique but interesting level aesthetics from scratch.
Thanks again for your interest in the team and I hope to see another application in the future!