>>831458
Crazy tricks implies exploring the hardware, not just coding to a library. You could theoretically do that and hit your GPU directly, but unless your platform is something like raspberry pi board with everything integrated, you run the risk that few other people will be able to watch your demo or play your game. And anyway, you'll never get anywhere close to the modern hardware limits. People still haven't fully explored computers from the 80's yet. Check out this demo from 2011, it completely turned the Amstrad CPC scene on its head and yet the authors admit that more experienced groups could do much better still:
http://www.pouet.net/prod.php?which=56761
And anyway you won't be able to do much exploring with modern hardware because the OS keeps you in ring 3. Before computers got all lame, your code was literally running the whole system, it was the OS so to speak. The closest you can get to that now is TempleOS. Of course this doesn't solve the incompatibility problem, where every modern PC has different sound and graphics hardware. But it's closer, more authentic to the old school because at least he enforces the same screen resolution, color depth, and limits you to the PC speaker only. So it's kind of a pseudo-compatible layer running in ring 0, to pretend you got a modern C64.
Well here's a VIC-20 demo (for stock machine with 5120 bytes of memory) where he actually uses lots of tricks he figured out himself:
http://www.pouet.net/prod.php?which=10626
Same thing with Trixter's 8088 demos:
http://www.pouet.net/user.php?who=819
Those guys are actually doing crazy tricks. Just using library in ring 3 isn't going to get you anywhere near that.
Bonus video: here's a recent production for Atari ST, just released at demoparty a couple weeks ago:
https://youtube.com/watch?v=IeyJkV8d8qc