I messed around with it a bit more. Overall, I mostly figured the idea is to use "not that many" tools (maybe due to that one objective requiring use of no more than 4), so setting up physics machines all around just to make trampolines do fun things seemed like an overkill. Now that I've tried it, yeah, it can work, but it's still very inconsistent. Hit the edge of the trampoline and all the momentum dies. Log is rotating during flight - more landing randomness. Two or more logs? Collisions mid-air, collisions on the trampoline, collisions everywhere. And once a trampoline messes up a single log, more will come and things will eventually break.
They work okay for dropping logs down a cliff and bouncing them at 45 degrees or something (as long as there's not too many logs), but for anything else I feel like I need to get the logs up first to get enough gravity for falling logs to make decent use of trampolines. If I use fans for vertical momentum, I don't have enough horizontal, if I use them for horizontal, I lack vertical and at that point I might as well just slinghshot things with a single fan and a slope. I tried going through the game by only using trampolines, but it's a bit tedious. I can't even guarantee the first log dropping properly on a trampoline right below the tree, because the position, orientation and velocity of spawning logs are not consistent.
Other than that a button to remove all tools would be nice, like there's one to clear all logs. And some sort of tutorial/tooltip on how experience is awarded, cause I haven't seen anything about it. And while exp for finishing objectives seems somewhat obvious, even if it's not written anywhere, exp for combos of 5x and above for the first time it's reached in a level was unexpected.
i'll add an option to remove all tools to the right click context menu - and yeah, i didn't communicate the new combo pb xp bonus you are right! Partly because i'm not sure about it as a scalable idea so might drop it and introduce something else, but yeah not good to have systems which aren't communicated!