Big TT Trickrace 1

Back in 2008 I did a tool-assisted run of this challenge, and was disappointed to see that it only resulted in a 27 turn run, just like the top non-tool-assisted replays. At the time I thought it was impossible to do better than 27 turns.

When this challenge was hosted here on TUS and there was a 5-way tie for first place at 27 turns, that only confirmed my belief that 27 was the best possible.

I was wrong. Here it is TASed in 23 turns: 2017-02-24 19.39.24 {TA} 2017-02-24 18.27.41 [TCB Challenge 63 - 23 turns] 0xDEADC0DE.WAgame

The trick is

Spoiler! View

to shoot from outside the cat, standing the left or right edge of its long belly. That way, the shotgun crater can be much higher, relative to the highest crater so far, than it could be when only shooting at the top edge of an existing shotgun crater from inside the cat.