Well, things are exploding, in a good, intentionally-when-I-press-the-BOOM!-button way.
Once it was working, I lost some time to moving the ball around with explosions :) It's certainly possibly to queue up several charges with time delays to give the ball multiple kicks in a single detonator press (i.e. 'stroke'), but it turns out that it's actually pretty difficult to guess times and distances off the cuff - this game has a lot of room for skill development.
With this done I can definitely get a playable, though limited, game working by the end of the game jam. I'm around step 30 on my dev plan (with a bit of bouncing around the order), and the minimal game emerges around step 35. Once I'm at that point I'll have to decide between implementing more game mechanics or adding prettier assets (images, sounds, a help/directions screen,...minor things like that...). Which way I go will depend on what kind of mood I'm in when I get there, but I give it 2:1 odds that I'll end up working on the mechanics - I expect the kind of assets I can create and use/implement in an hour or two won't greatly improve the play experience.
time spent coding this evening: 2.5 hours
jam time remaining: 5 hours