You have the strangest feeling of deja vu...

Yesterday, we received a mysterious transmission from a previously unknown exoplanet. Our best scientists have been working around the clock, but so far all they've figured out is that it contains codes for two VR games. Seeing as how there is so little grant money in the area of "free games" (probably because publication always leads to ninja infestations), they have elected to assign this research to their graduate assistants.

...That would be you. Here's the transmission. Get to work.

Meanwhile, the military has decided to take action against this clear threat to world economic stability. You only have seven days before the fleet arrives and nukes the site from orbit. It's the only way to be sure--unless you crack the code first.

Good luck.

Apologies for the short duration. I only decided to make it into a puzzle after I'd already created the giveaways. D: Fixed. Now there's a reasonable amount of time to solve the mystery. (Giveaways end on August 5th.)

As usual, I will be adding hints at random intervals. The first one is rather necessary to solve the puzzle, but the rest will be optional.

Hint 1: All but the first two letters of the transmission are capitalized.
Hint 2: Numbers come before letters in alphabetical order.
Hint 3: Only one of the codes contains numbers.

Solution:
The transmission consists of a simple substitution cypher. Two main questions must be answered to solve the puzzle: What is the key to the cypher, and which direction is the transmission read in?

Hint 1 simplifies the possibilities considerably. There are 26 letters and 10 numerals, a total of 36 possibilities. If capitals were encoded separately, there would be another 26 letters, bringing the total to 62. Since the highest number in the transmission is 31, we can safely assume that capitals and lowercase are not encoded differently.

Hint 2 leads to the key to the cypher. The transmission doesn't contain enough characters to do a statistical analysis, so the key should either be found in a secret keyphrase hidden in the description of the puzzle, or it could simply be the alphabet in order. By referring to alphabetical order, this hint implies it was the latter, and that the numbers 0-9 come before the letters A-Z. Therefore, we have the following key:

00 = 0     06 = 6     12 = C     18 = I     24 = O     30 = U
01 = 1     07 = 7     13 = D     19 = J     25 = P     31 = V
02 = 2     08 = 8     14 = E     20 = K     26 = Q     32 = W
03 = 3     09 = 9     15 = F     21 = L     27 = R     33 = X
04 = 4     10 = A     16 = G     22 = M     28 = S     34 = Y
05 = 5     11 = B     17 = H     23 = N     29 = T     35 = Z

Hint 3 gives us the final piece of information we need. There are two obvious ways of reading the transmission: left-to-right or top-to-bottom. (The begin and end transmission cells eliminate right-to-left and bottom-to-top as possibilities.) It would be simple enough to try both, but looking carefully you can see that top-to-bottom produces two codes with numbers. Therefore, left-to-right must be the correct way to read the transmission.

Having worked all that out, the transmission reads "23 21 24 31 16 21 25 19 08 06", which can be deciphered into "N L O V G L P J 8 6". Group by fives and lowercase the first two letters for "nlOVG LPJ86". Plug those codes into the appropriate URLs, and you get links to the giveaways: Archangel Hellfire - Fully Loaded and Star Trek: Bridge Crew.

I had fun making this puzzle and hope you all enjoyed trying to solve it! Let me know what you think in the comments. :)