nxengine-evo VS VVVVVV

nXEngine-evo - Cave Story clone. C++, SDL2

Or this improved version: https://github.com/nxengine/nxengine-evo

Dwarf Fortress N Cave Story Powder Toy Knytt Stories

NXEngine, later NXEngine-evo: While these engines are notable for historical reasons (and being ported to a bazillion different platforms over the years), they're very inaccurate to the original game so it's hard to recommend these anymore.

Build Cave Story (nxengine-evo)

Seriously? https://github.com/nxengine/nxengine-evo/releases

NXengine (or nxengine-evo), an open source engine that can be used to play cave story. Apart from some minor bugs a really good way to experience the game. https://nxengine.sourceforge.io/ https://github.com/nxengine/nxengine-evo

All of these are games I've put countless of hours into. There's a bunch of other good games, SuperTux, Pingus, Tux Racer, Neverball/neverputt, Minetest, 0ad, some of the KDE games, and more that I've played and liked but haven't lost nearly as much time with.

There also a direct port of cave story for the vita and it's excellent. https://github.com/nxengine/nxengine-evo/releases. It was updated a few months ago and worth checking out.

Play Cave Story. It's free and one of the greatest indie games ever made. :) Also check out Super Tux Kart.

*The Monkey's Paw curls* https://github.com/TerryCavanagh/VVVVVV

VVVVVV at least has since become open source.

VVVVVV - A platformer where you flip gravity instead of jumping. Was recently open-sourced to celebrate the game's 10th anniversary!

Yeah, just look at this beauty! https://github.com/TerryCavanagh/VVVVVV/blob/master/desktop_version/src/Game.cpp

Finally, games are really that complex. Check out for example Terry Cavanagh's blog post on releasing the source code for VVVVVV, and check out the source for Game.cpp (although keep in mind this was ported from ActionScript).

So it seems to be an unofficial policy rather than a written rule, if those allegations are true (remember that those are Wolfire's claims of what Valve said). Certainly there doesn't seem to be consistent enforcement - for instance Tales of Maj'Eyal is free, but $7 on Steam. Apparently there are some minor differences - does that mean that they can claim that it's a "separate version" and hence doesn't need price parity, even though 99.9% of the game is identical? There's also VVVVVV, which is open source (albeit years after initial commercial release) where you can freely build the exact same copy as on Steam ($5), including steamworks support. Does that count as a "separate version" when you just have to compile code? Admittedly these are two indie games, albeit extremely well-known ones, but then - isn't Wolfire Games also an indie studio?

I think it's worth noting VVVVVV has actually been open-sourced https://github.com/TerryCavanagh/VVVVVV