My partner and I are in the midst of developing a hybrid game of sorts. The style is largely action-adventure (battling overworld monsters, collecting and using items, solving puzzles, etc.), with a bit of RPG mixed in (particularly with levelling and weapons/skills/powers that can be upgraded). There are also some visual novel-esque elements (text boxes/character illustrations with changing expressions that come up during certain conversations, CGs/cut-scenes). And lastly, there is a large emphasis on player actions/decisions affecting how the world changes throughout the game, along with attaining various possible endings.
Our goal is to release this game on Steam. Ideally, we'd like an engine that's capable of releasing builds for Windows, Mac, and Linux. Additionally, we'd like to be able to release patches for the game if needed. And, we want the ability to add both keyboard and joystick controls.
What do you think would be the best engine to use for something like this? We're considering adding some animation to the character illustrations and/or CGs, if that makes a difference.
Any assistance at all would be greatly appreciated!
Side Note: We're already familiar with Unity, but we're both pretty new to the world of programming. We were hoping to discover some other engines we may not be aware of.