Press F2 in Fallen Aces and become MOUSE's Jack Pepper: all 10 hand-drawn guns, his HUD and voice, upgrades bought with Duke City cash.
Play Fallen Aces' own chapters, then press F2 and Jack Fist hands the case to Jack Pepper from MOUSE: P.I. For Hire. His rubber-hose hands, guns, HUD and voice are read from your own copy of MOUSE, and every shot he fires is one of Fallen Aces' own rounds, so goons stagger, get knocked down, bleed and die the Fallen Aces way, and they hear the gunfire.
What you get
Needs Fallen Aces and MOUSE: P.I. For Hire installed. Nothing from either game is shipped: the first start reads Jack's arsenal from your MOUSE folder (about a minute), after that it's instant.
Made by Josh Rader with Claude. MOUSE: P.I. For Hire is by Fumi Games; Fallen Aces is published by New Blood Interactive. Ships BepInEx 5 (LGPL-2.1), HarmonyX, MonoMod and Mono.Cecil (MIT), AssetsTools.NET (MIT) and vgmstream (ISC) with their licenses.