Yeah I love this short film.
The whole video is about time. How it's relative (the more time you have experienced, makes the present feel shorter in comparison). He's obsessed with it.
This is my opinion, I think at the end he becomes so obsessed that it becomes unhealthy and he becomes unstable (he cuts all the heads off his insects). The scene where they are giving him the eagleman stag serum or whatever, I think they are performing a lobotomy on him (the drill). And as he says, he wanted to experience the feeling of 'infinity' again. And by doing that, he can. I feel like this is confirmed in the end scene where that man is talking to him in a condensing tone (like he's been put in an institution).
And I read somewhere that those cubes and the whole "inanimate object" line are about our lives. The cubes are each person, and the cube morphing into a plant shape for a brief moment represented his/our life. It was just a flicker in comparison. So yeah, all relative.