Fantastic! You have indeed finished all the current content. The Rakshasa boss is the last level for now, but more is coming soon!
We'll be releasing a blog in the next few hours outlining a rough Early Access schedule. I'll save the details for that, but in general terms, we should be patching weekly, with every second patch offering new story content.
Your guess is correct! Chapter 4 will see the three heroes meet up for the first time. It is quite a few hours in, but Guile & Glory: Firstborn will be a fairly long game, so there will be plenty to look forward to once the heroes team up!
We love the idea of being able to replay levels with a team of your choice, and having some later levels where you can pick your party as well. We can't confirm right now exactly how we'll implement it, but something like that is definitely in the works!
We're also really glad to hear the game is bringing back fond memories of some old-school favourites. We love The Lost Vikings, and games from the Megadrive / Genesis era in general, so it's nice to know we're hitting the right notes!