A nice and original game that I enjoyed to repeat even after I finished it on ArmorGames.
For everyone struggling with the <3x25 level: to correct the glitch, place the explosive block exactly on the wood block, so that it would fall in. Once you shoot it, the explosion animation is supposed to fall inside the hole, meaning the path now is clear.
SPOILER ALERT!
The glitch comes back in the <3x3 level, where you have to use ****** to climb up and reach the gun; the glitch turns into a permanent invisible wall every block where you placed ******, so pay attention to how you move it.
That is all, and like Karoshi said in description, have fun (killing yourself)!