We're working on an updated version to be released near the end of the month.
It uses my newer input manager to replace the crappy Unity one. Currently it's configured for X360 controller and to modify it you have to use the garbo unity input manager when you start the game. The new input manager I wrote auto-detects most controllers, and has an in game menu to change inputs if you don't like the default.
We can not move to a newer version of Unity for this game. We will be moving to the newer Unity in our future games after this series is done.
Splash screen removal requires premium Unity. We are not currently at the budget level to afford doing so (this is a 2-man project done in our garage).
Inputs are defined in the title screen under 'Controls'. In the newer version that comes out later this month the controls screen will also appear in the pause menu. On keyboard/mouse you hold right click to aim, and left click to fire (if you're on mac with one button mouse, you're sort of shit out of luck in the current version).