If you were to add some background music, a background, and a gimmick it would make it 5 stars.

It's actually a really fun game, but it really needs instructions.

My first impression of the game was that it was really slow. It became interesting toward the end to try and keep the bigger numbers at the bottom, and to rectify your mistakes by sneaking lower numbers down to match with any stragglers you left there by accident. However, when I realized how many more ways there were to combine numbers, I had to completely reevaluate my strategy.

I didn't realize you could select more than one number to combine, that you could combine multiple items that weren't in a row, or that you could combine different kinds of numbers (for instance 8+8+16.)

Even after learning this, it seems like the safest way to play is to combine numbers two at a time, so that you're not surprised by tons of tiles coming in at once. Small moves mean fewer new tiles, which means it's easier to change your plans gradually according to what comes up.

This should be balanced out by big combinations rewarding you with bonus points, but unfortunately it's not clear how the scoring system works, you just see your score go up. I notice 2+2 gives 2 points, 2+2+2 gives 3 points, and 2+2+2+2 gives 4 points. 4+4 gives 4 points, so it looks like the points you get are just the base number times the number of tiles you combine it with? The player could get the same number of points by combining them individually, with the added benefit that they have more opportunities to keep small numbers from falling to the bottom.

Currently it's possible to combine a whole screen of 4s into 128 and have the respawning tiles bury a 4 beneath a huge tile. This heavily disincentivizes big combos as it's risky and doesn't give any sort of bonus at all. Generally I found it was only useful to do big combos to combine odd numbers of small numbers I was trying to get rid of, or if I combined straight down so that I could ensure big numbers fell lower.

- Add some instructions for the player.
- Allow the player to click once and roll over tiles to select multiple, and preview what number you're combining to. This will make it easier for players to know what number they'll end up with if they combine a bunch.
- Add bonus points for combining more tiles, and display the point value of each move with a popup (for instance, 2+2+4+4 = 8 points x2 bonus = 16 points.) Reward the player for big, risky combos.
- More colors after 512, it's easy to cruise past this number and it's visually hard to play after that point.

Cool concept but missing some things that would balance it.