Okay, Triangle probably isn't actually the name of this escape game by SuzumeDr. Its actual name, as far as I can tell, is "?" (a solid black equilateral triangle), but I'll be darned if I can figure out how to type that into the title box, so let's settle for the word the symbol represents: Triangle.
It's played just like most escape games. Explore the room, pick up various items, solve various puzzles, and eventually regain your freedom. To use an item, click it once and then click the environment; to examine it closer, double-click.
So what's different about this one? The atmosphere. Triangle is absolutely charming. Its atmosphere is decidedly different from practically every escape game I've ever played before, and for someone who's played as many as I have that's a feat.
The graphics are almost entirely made out of triangles (hence the name, I presume), and 90% of it is either black, white, or red. Most of the sound effects seem to have been recorded using percussion instruments, which has a charm all to itself (my personal favorite is the "dee-dee dee-dah" that means "you try to open this thing, but it's locked").
But the meat of an escape game is its puzzles, and Triangle is strong here as well. Every puzzle is fairly intuitive, but still a bit challenging. There are touches of originality, but also a few samples of the familiar, including the mandatory arithmetic puzzle that will send you rushing for a calculator. The little extra touches, like how used items show up on the nightstand next to the door, don't go unappreciated either.
Triangle is not a game to be missed, unless you're a square. Or a circle, or a pentagon.