A PlayStation alternative to Xbox's increasingly popular Game Pass subscription service has been a seeming inevitability for some time. That plan was unofficially confirmed when leaked details regarding PlayStation's Project Spartacus spread. Spartacus was said to include both PlayStation Plus and PlayStation Now in three different tiers of subscription. Now even more information regarding PlayStation's Spartacus plans have been leaked, including what may be a key way Sony plans to make Spartacus unique and attractive.Games Beat's Jeff Grubb shared the latest Spartacus details in a recent episode of his Giant Bomb show Grubbsnax. To start, Grubb re-confirms that Spartacus will be broken up into three different tiers. The tiers will retain the PlayStation Plus branding, but with additional labels -- Essential, Extra, and Premium. These tiers will then be priced at $10, $13, and $16 a month, respectively. What each tier includes is where things get interesting.RELATED: PlayStation 3 Games Now Visible in the PlayStation 5 StoreThe $10 PS+ Essential Tier is said to be what PS+ is currently. It supports multiplayer game access and a small collection of monthly games that subscribers keep so long as they remain subscribed. For $13, subscribers gain access to a catalog of video games akin to Xbox Game Pass. Gubb characterizes this as PlayStation Now's library of games, but without the cloud requirement. The $16 Premium subscription includes all prior features, as well as PlayStation Now cloud streaming, "game trials," and most excitingly, access to a special reserve of "classic games."

Exactly what "classic games" implies isn't entirely clear and neither is "game trials." If speculating, the library of classic games could perhaps be akin to Nintendo's library of classic games included with its Nintendo Online and Expansion Pass subscription. Games from previous console generations that are no longer available, except through the subscription service, would certainly grab some subscribers' attention.

As for game trials, it perhaps hearkens back to Xbox Game Pass' biggest strength. Game Pass delivers day one first-party releases to subscribers for no extra charge. PlayStation may be unwilling to go that far, as is Nintendo, but offering game trials instead is one option. Players could try out the new God of War: Ragnarok or Gran Turismo 7 for a couple of hours and then decide if they want to make a full purchase.

Given the detail stemming from this recent round of PlayStation Spartacus leaks, a release is likely nearing. Grubb says that a testing phase for the subscription service tiers is planned to start in the "next few weeks." Beyond that, an announcement could be made in March, as well. Fully launching the service, however, will depend on PlayStation's ability to deliver the service, which may take some additional fine-tuning. Expect to hear more about Sony's PlayStation Plus changes soon.

MORE: It Seems Unlikely that PlayStation's Project Spartacus Would Ever Include Day One First-Party Releases