The update I just did features such a major rewrite that it's not really a direct copy. Also, the reason I rewrote it (not just to copy your work) is because, though your scenario is in the reusable/support actors collection I found the code pretty obfuscated.

In the spring class, it would make the code more readable to change the places where you do "Math.sqrt(Math.pow(someValue, 2) + Math.pow(someOtherValue, 2))" to "Math.hypot(someValue, someOtherValue)"

I'm well aware of how to implement better jumping (see http://www.greenfoot.org/scenarios/4547), I just hadn't got round to it. Thanks though, I'll remember to do it soon.

Yeah, if I put the speed slider to max (so it's not capped at 60fps) it'll run at speeds of 120-180fps - so yeah, like I said, I'm not personally getting any lagginess. I'm still busy, but like I said, I'll make some optimizations later.

I was wondering if and when someone was going to say it's laggy - problem is, my computer's quite good, so it runs at a solid 60fps for me. I'm fairly busy, but if I have time later I'll try and make some optimisations. And yeah, I'll block the ends of the map