Against the Wall (in-browser through Unity, download also available) is a 3-D, first-person perspective game current in Alpha in which you are tasked with traversing a sheer wall-face. Clicking the mouse will cause the blocks that make up the wall to protrude or retract, allowing you to puzzle your way through a path that will lead you (presumably) higher and higher. Some small touches make this utterly compelling: the blocks have momentum and can push you off your footing; if you're standing on a block as you command it to protrude, you'll be carried along with it, away from the wall. There also appears to be at least one civilization built up along the wall. In this Alpha build, there are at least three events/surprises for you to discover. The final release (date unspecifies) promises much more.
Note: I couldn’t figure out how to actually restore from a checkpoint (other than immediately after the one actual pre-finale end-game condition I found). Thus, it’s recommended that you use F5/F9 to quicksave/quickload as necessary. Falling off the wall seems to allow for infinite plummeting, and while you could theoretically climb your way all the way up to where you started or where you fell from, it’s probably not worth your time. (I didn’t see any special content below the starting platform).
Note #2: On the first starting platform there is an object you can carry. I thought it might be fun to try to carry it all the way to my (presumed) destination. If you try to do the same, note that quick-loading currently seems to reset that object back to the starting platform. Likewise, there is at least one event that I found sent the object plummeting into the infinite unknown.
Note #3: I came across this game with no information beyond “infinite wall.” I hope I haven’t spoiled the experience by saying there’s more to it than that.