Hah, the reason my ocean scene looks somewhat fudged is because it's an old version. The newest version, which contains water fog and an ocean floor, is on my "Boss Rig" computer, which as of yesterday has a dying power supply.
Jedi :
Your nature scene is excellent, however I would suggest you look over your converted palm trees. A few of them have only one-sided textures and in others, they have a transparency glitch so nothing behind them shows up.
I would also suggest you remove some of the low detail vegetation, such as the Alice palms. It's like seeing Pac-Man in BF3.
ArtyFish-L:
In your Realistic Sea scene, I trialed the exact same water texture. However, I noticed that it would
only work if specularity and normal maps were working. You seem to have done a nice job on the horizon. The only thing I would suggest is that to make the camera not-stationary, you can use distance clouds instead of the ones you use now. Distance clouds are 2D clouds meant to be placed far higher than the player could possibly move, and because of this can make a scene extremely realistic, provided you use realistic distance clouds. You can also use an HDR Panoramic Skydome in conjunction with these clouds so that you don't have to place quite as many.
The link to your jungle warfare scene is dead, so based on the screenshot I'll say you ought to replace the Alice Fire with a rising smoke pattern. Smoke, unlike this fire, is better at making the illusion that it is 3D. For an example of this,
Masahiro Ushiyama at 1:37. I will note that instead of 2D smoke, he is using particles to simulate the vapor trail, however the principle is the same.
Your grass texture is good. I cannot see a pattern and it tiles very well. If someone imported some vegetation as well as wild grasses I bet they'd be able to make something nice.
Your concrete is bad. It's not tileable and the pattern can be easily seen.
Your dirt tiles, but the pattern is noticeable. Textures of this type can be fixed by adding lots of brush to distract from the ground.
If your cracked ground was tileable, I would have been fooled to think that the ground had poly depth. If you can make this tileable I expect you'll be able to make a very good desert scene.
I suspect your forest tile will make a very nice scene once the pattern is covered by brush... and trees. It will also be noticeably better if you work with realistic brush rather than cartoony brush.
Aagh, untileable lava. For the sky, you can use Photoshop to turn a regular HDR Sky from blue-white to reddish-black to simulate the ash clouds and excess metal in the atmosphere.
Good choice in snow. I can see the pattern but that's fine. A good use of this scene is a snowy alpine mountainscape. The sky color you chose is also good, the horizon seems blurred.
Sea's not tileable, I also see evidence of the need of a specularity and bump map.
Your sand isn't tileable, also even if it were there's too many defining objects that give it an extremely obvious pattern. When you look for a terrain, you want something that, besides being tileable, has very few major details so that you can't look at a spot and recognize which part of the tile it is.
I also trialed this exact same water texture. I thought it didn't look very much like water, especially without the other two maps.
Your space (moon?) scene's ground texture lacks tileability and has that pattern. Personally, I don't think it would work well as a rocky surface even if it were tileable without a pattern. Perhaps it would do good as a castle wall or a cliff wall.
ArtyFish's best scene IMO was the snow scene. Despite how I could see a pattern, the rest of the scene's parameters were altered to be very convincing.