A while back Marta Maksymiec and I made a small game for LowrezJam 2017 on itch.io. It is a two player racing game in which you collect coins to win the race. You can play it online or download a PC build here.
As you can probably imagine, the goal of the jam was to make a lowrez game - it had to be made in 64x64px resolution.
We made it on Unity3d and decided to deploy on PC and WebGL. WebGL seemed to be a perfect Flash replacement but actually I had tons of unexpected issues with it. If you are ever going to use it do some tests first!
It has some serious limitations such as very low amounts of sounds which can be played at any moment (I think maximum is six), resolution is an issue (I couldn't set it to 64x64px for some odd reason) and getting performance right is very tricky. Documentation is sparse and you won't find a lot of resources about it on the Internet. My fellow programmer told me that amongst all platforms he worked on, WebGL is the most labor extensive. And I believe him as he even made applications for intelligent pencils.