Next up is Cuba Letra, a free game from Charlie Dog Games. It's not often you get a really engaging free game, especially one that iterates on the formulaic build-a-word gameplay.

You left-click letters with your mouse to build words; right-clicking submits the word. Longer words net you more points. If you make an error in your letter selection, you can either click the offending letter to remove it from the build queue, or click the Cancel button to start over.

In the left-hand UI, you have a Target meter that fills up as you complete your various words. Filling it to the top finishes the level and sends you to the next one. There is also a section for the Bonus Word, which is usually something fairly long and unusual, like "exhumed". You don't need to spell this word out specifically; each word you create, if it has letters from the Bonus Word in it, will fill the word in incidentally. Once the Bonus Word is complete, you'll receive a lot of points.

What makes Cuba Letra so interesting is the fact that the letters you're given to spell words are arranged along a path, emanating from a single point. As each letter appears, it pushes the whole line of letters toward an end point; if the terminating letter enters the destination, it's Game Over.

The line of letters moves along at different speeds, depending on two factors: 1) each level has its own speed at which it spits the letters out, and 2) if you're completing words at a rapid pace, the letters will appear more rapidly to fill up the space. If you make a word out of letters derived from different points in the line, the entire line's progress toward the end point is halted until new letters can push the line back together.

Forming words that are very short -- three or four letters, typically -- too often in a row will cause certain letters to turn red. This means that they'll start creating new letters on their own, at rates faster than the normal spawn rate. To stop this from continuing, you must use the red letters in your next word.

Different levels display different, and sometimes multiple paths toward multiple exits. This can make forming words much more difficult, as sometimes one line will contain nothing but vowels, while another line will only hold consonants. I discovered that I fall victim to my inability to skip around a line to form a word; it's easy for me to get stuck "reading" a bunch of letters to form a nonsense word, which makes it hard for me to come up with a viable word on my own.

Occasionally, a golden letter will appear. Choosing to use this letter in a word grants more points than normal letters do. Additionally, a letter might cause the line to stop moving entirely when used in a word; this gives you 40 seconds to choose the next few words, free from the anxiety of the time restriction.

A major issue I had with Cuba Letra is its lexicon. I frequently created words that the game didn't recognize, which is a frustrating experience when time is an issue. In general, however, the game is a lot of fun, and unexpectedly challenging in novel ways. You can grab the demo right here on Big Download for Mac only.