Mike D'Angelo’s review published on Letterboxd:
Key word being "blank." This was such a bizarre moment in American film history, never to be repeated; for a limited time only, studio's bottom-line concerns about maintaining viewer identification were suspended. I'd vaguely recalled Marvin doing his typical badass thing, but Walker actually comes across here as wearily put-upon, like a man determined to get reimbursed for a mistaken charge on his credit card. (It's a running "joke" that none of the baddies can fathom why he'd expend so much energy to recover the relatively paltry sum of money that was stolen from him.) The deliberate absence of almost any context leaves us watching a singleminded void wreak meaningless havoc, culminating in a mysteriously unresolved ending that declines to show Walker achieve his goal or fail to achieve it*. Boorman is unmistakably making an art film in flimsy genre disguise, experimenting with non-linearity and various disjunctions between sound and image, but Point Blank's emotional abstraction would turn up again the following year in the more formally straightforward Bullitt. A reaction to the turbulence happening offscreen at that time, no doubt. Maybe it is to be repeated.
* I'm familiar with the Owl Creek Bridge hypothesis, which is interesting but seems unnecessary, somehow.