You have the ability to toggle back and forth between how the game originally looked, and how it looks now, and holy moly the difference is night and day. Thanks to the new lighting, shaders, and other technical enhancements that flew way over my head, Manny and company now look incredible. Their in-game models appear to be nearly identical to their cut-scene counterparts, which is great. The game is still presented in 4:3, but you have the ability to stretch it to widescreen (for the love of everything good, please don't do this). The borders are black right now, but I was told that the developers are toying with some ideas for what could stand on the two sides of the screen.
Gone are the tank controls, aka the bane of existence. Now you can navigate the Day of the Dead-themed world as you would any other modern 3D game. This makes puzzle solving and exploration even more enjoyable than it was before.
The final big change I stumbled across was the awesome inclusion of nodes scattered throughout the world that contain small snippets of commentary from Tim Schafer, Peter Chan, Peter McConnell, and a ton of other folks who helped make the game so special back in 1998. The handful of ones I listened to provided interesting and hilarious insight into the original development of the game, the work done on the Remaster, and everything else that’s happened over the past 15 years. I adore the commentary in Portal, and I'd be willing to bet I'm going to love it here just as much
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Improvements sound great.