I agree—this game is really frustrating because it's difficult to see the barriers. Challenging games are often frustrating, don't disagree with you there - but this particular flavor of challenge isn't really fun. I'd prefer "it came too fast" or "it was moving and hit me" to "the wall looked just like the opening." I definitely got better after my first few plays at discerning the walls from the openings, but it took me a few tries to even realize that that's why I was dying. I imagine many people will give up before I did.

Just chiming in to agree with this. Games that are difficult because of their UI usually aren't very fun.

Also, it seems important for the game to quantize input. I.e. right now you can occupy a continuous height anywhere from "0.0 to 1.0", but it would be much more fun if the game would automatically snap your height to either "bottom, middle, or top." It's quite frustrating to lose because you just barely clip a gate.

I didn't realise it was a continuous range of heights, 3 set heights would definitely be better as the holes are at set heights. Fantastic game and music, though. Really demonstrates how capable WebGL actually is.

Even worse. I found myself in situations where I cleared the middle section of one gate and, without any movement on my part at all, hit the next gate even though it also had an open middle section. This happened to me twice with a gate at the top of a ramp.

I'm confident that I didn't move the ship because I used the arrow keys and positioned myself well before reaching the first gate. I was close enough to missing the opening that I would understand hitting the first gate, but hitting the second gate is uniquely frustrating.

Try using arrow keys, it does exactly that.

No, I won't, because when frustration_value > fun_value I stop playing immediately and never come back.

Failing because I wasn't quick enough can be fun. Failing because your overly-clever graphics engine requires me to distinguish "fog" from "glass in fog" in 0.5 seconds is never fun.