I've been enjoying the game so far, and I got the surfboard upgrade which says 'LT to surf', but no matter what I do it doesn't come up and I lose health jumping into the sludge. I tried going to the shop and didn't see the guy selling his surfboard, so I don't know what to do.

On another similar ability, I bought the speedometer, which purports to tell me how fast I'm going in MPH, but I can't see it anywhere on my screen.

As an aside, dive kicking enemies infinitely works well for damage, as only one or two enemies I've encountered have any ability to harm me if I don't screw up my timing