First things first: The surface aspects of Helios are outrageously good. The production value rivals Hollywood films with convincing large scale sets, international location shooting, subtle photo-real CGI, gorgeous cinematography, and rip-roaring action scenes. Speaking of action scenes, Helios' gun battles are firmly in the new wave of Hong Kong gun play: Hard-hitting machine gun battles with a dash of real-world tactical flare. They resemble more the thrilling shootout in Michael Mann's Heat rather than John Woo's elegant work. This action style works well for thrillers and HK cinema have gotten damn good at it in recent years.
Sadly, Helios' plotting and narrative are also notably Hollywood- esque with shallow characters, contrived emotions, and ludicrous plot all held together by tightly paced editing and actors that demand you look at them due to their great acting or great looks. It all still manages to be compelling, but none of it holds up on reflection. Despite its flaws, Helios could normally be recommended as a fun "turn off your brain" action thriller and that would be that. Alas, the ending makes the recommendation much harder. Without going into specifics, just know that there is no satisfaction to be had in any way. No closure, no justice, no explanation. Viewers will have to decide for themselves if it's worth watching a movie that entertains mightily then reverses all of that good will in the last 10 minutes.