(2014) and Shadowrun: Hong Kong (2015) quickly followed. An online tactical game not directly related to the previous three games, Shadowrun Chronicles: Boston Lockdown, was released to less-than-positive reviews in 2015. In 2014 the tactical RPG Blackguards based on the German The Dark Eye pen-and-paper setting was released to mixed or average reviews. A sequel, Blackguards 2, was released in 2015. 2015 saw the release of Invisible, Inc. for OS X, Windows and Linux. It has been described as a "tactical RPG that mixes stealth with procedural generation", since it introduces elements of espionage and roguelike gameplay. It received generally favorable scores from reviewers. A version for the PlayStation 4 and Nintendo Switch has been released. In March 2017 the German indie developer Overhype Studios released its tactical RPG Battle Brothers out of Early Access to generally favorable reviews. This mercenary company simulation was described as a "cleverly constructed, carefully balanced board game". Genre blurring Other games combine similar mechanics, but typically belong in other genres. Tactical wargames such as the Steel Panthers series (1995–2006) sometimes combine tactical military combat with RPG-derived unit advancement. Avalon Hill's Squad Leader (2000), a man-to-man wargame utilizing the Soldiers at War engine, has also been compared (unfavorably) to X-COM and Jagged Alliance. Rebelstar (1984) and Laser Squad (1988) were precursors to X-COM created by the same developer, Julian Gollop. They did not, however, feature the statistical character development and strategic map of the later series. Bokosuka Wars (1983), a game regarded as the progenitor of the strategy/simulation RPG genre, is also difficult to clearly define. While often referred to as a strategy/simulation RPG, it is also sometimes referred to as a prototype real-time strategy, an early reverse tower defense game, and an early action role-playing game. Nobunaga's Ambition (1983) and later Koei titles as well as Capcom's Destiny of an Emperor (1989) have blurred the line between a role-playing game, turn-based grand strategy wargame, and simulation video game. Similarly, Kure Software Koubou's Silver Ghost (1988) combined elements of both tactical RPGs and action RPGs, while Ogre Battle: March of the Black Queen (1993) blurred the line between a tactical RPG and a real-time strategy. Metal Gear Acid (2004) blurs the line between a stealth game, a genre the Metal Gear series is normally known for, along with tactical role-playing inspired by the likes of Fire Emblem and Final Fantasy Tactics, infused with card gameplay