Tl;dr: Yes, it’s definitely worth $7. It’s 11p per level. You might as well buy it; it’s probably better than all the crap you bought in the Steam sale and have never played with.
Swift*Stitch, it turns out, is not a tailoring sim, but “a game about going fast, taking the right route and trying not to crash into stuff”. ‘Swift’ presumably alludes to the blinding speed, and ‘stitch’ to the warp- and weft-style movement, as well as the slightly stitched appearance of the boingy walls. S*S has essentially two controls: hold the left mouse button to move your little ship vertically, leave it unpressed to go horizontally, boing off coloured walls to switch direction. It’s bloody hard. It elicited many angry mooing sounds. It’s also great fun, holding my interest more than my other recent purchase of Bejeweled 3.
It’s a challenging game, but S*S is wonderful in its implementation of non-guffbeakery. The learning curve is sensible. If you get it wrong, it’s always your fault. You can play any level whenever you want, instead of having to play through a level to unlock the next one (a wonderful bit of design that shows this game is meant for playing). The game invites you once and only once to switch to a lower speed should you crash like a sugar-rushing monkey. No remapping needed for a left-handed mouse. Don’t like mouse? Use keyboard instead.
The game also has some graphical goodies, such as ‘Invert colours’ (surprisingly nice) and ‘WTF mode’, which adds confetti and motion-blur. The best of these is Cruel camera, which simulates the camera operation of that of Homer Simpson distracted by a butterfly.
S*S is available for Windows and Mac. I can confirm that the Windows version runs nicely under WINE, albeit with a bit of jaggy scrolling in any speed class above 3 (no impediment to gameplay; it’s just not as pretty). Unfortunately, you can’t try the demo in Linux, as it requires Unity web player.
Update: Hot piss! S*S is now free and available for PC, Mac and Linux!