The reaper

Spoiler: Hint to start

Between the two red blocks behind the skull, pull the block that will slide away by 1 block, which will release the two containers that were preventing the reaper from moving forward. By going up, enjoy the catapulting system on the bot that was stuck. Oh? Maybe it gives an idea for one star...

Spoiler: Hint for upper star

You have to bring the blue bot close enough to the reaper so that it dies, falls on the funnel, and then unlock the reaper to catapult the corpse on the star

Spoiler: Hint for going out of the inner loop

The loop is almost inescapable for the reaper, the only way out is to make a quick u-turn, can you find where? Yes... Close the loop at the right place.

Spoiler: Hint for star that R-bot avoids

Bots are currently synchronized to avoid going on the star. Kill the first blue bot, and ensure the reaper goes away, so that bots have the time to reorganize and eventually one will get the star. Then, kill them all.

Complete carnage inflicted by the reapermobile that trampled everything in its path. Great fun. Challenge collecting all the stars. I thought i had captured one by an alternative option but i see from the hints that it was the designed gameplay.

I had lots of fun with the reaper B killing everything in his path but couldn't figure out the way to get the star closest to B - the one just beside the two stairs slider. Help please.

@mastersifu

Spoiler: Hint with the two stair slider

Make sure the reaper mobile gets out of the inner loop, then when it reaches the slider, move it to guide the reaper mobile to the star.

Ah got it now. Thanks for the hint. I like the escape from the infinite loop and the reaper B was extremely cool. Thanks for sharing.

For me, the hardest part is the star to be grabbed with the zapper. It's very hard to guess -

Spoiler

it's hard to guess that you need to kill one blue zapper, then move the car away so that it doesn't kill the rest of the zappers, then they change their trajectory. And then the red zapper takes the star. It seems to me impossible to guess - you just need to know. Thanks for the tip. I was convinced that the car should kill the red zapper, and he will fall on the star. I have achieved this for about 8 attempts!)) And did not receive it!))

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Very good mechanism !! I give you 5 for the opening mechanism with the design of the skull and the mechanism of the machine.
I think this is the level at which the video walkthrough should be !!

Spoiler: Video walkthrough

@Denis Nazin Yes, it is hard to guess,

Spoiler

especially because I wanted exactly a mechanism that would not get you a star unless you killed only one zapper temporarily, and I found this one by chance after a lots of attempts.
That's why I gave the hint in the first description. Maybe I could have tried to draw some blocks that give the hint on the steps inside the world.

B's very own Mad Machine!!!
Was not easy to collect all the stars but it sure was a lot of fun watching all those Bots crumble in the path of B's mad machine