I tried this on slightly older hardware [1] running Linux Mint 13 x86_64 and here's what I found:
First, even scrolling the website itself was slow and jerky in Firefox 19.0. When I switched to Chromium 24.0.1312.56 the website scrolled nicely. The Flash version of the game ran somewhat choppily with Flash 11.0.1.152 and I could see distinct seams in the scrolling background [2]. However, it had sound and was overall playable. When I tried the HTML 5 version it ran smoothly but felt too fast (seemingly faster than the Flash version would have been with a good frame rate) and had no sound.
The total memory/CPU usage as reported by Chromium's task manager is higher with Flash [3]. Unfortunately, it doesn't report the frame rate for Flash.
Edit WRT the game's design: when I first played the game I went to grab a power-up and my ship apparently got enveloped in some sort of a bright and colourful energy ring. I couldn't tell whether that was a good thing that happened because I picked up the power-up or a bad thing caused by an encounter with a nearby enemy bullet. I had to watch the life counter in the top right until it happened again to know for sure that that's what it looks like when my ship explodes. The explosion looks bright, colourful and pretty, and it's not immediately clear it indicates failure.
First, even scrolling the website itself was slow and jerky in Firefox 19.0. When I switched to Chromium 24.0.1312.56 the website scrolled nicely. The Flash version of the game ran somewhat choppily with Flash 11.0.1.152 and I could see distinct seams in the scrolling background [2]. However, it had sound and was overall playable. When I tried the HTML 5 version it ran smoothly but felt too fast (seemingly faster than the Flash version would have been with a good frame rate) and had no sound.
The total memory/CPU usage as reported by Chromium's task manager is higher with Flash [3]. Unfortunately, it doesn't report the frame rate for Flash.
Edit WRT the game's design: when I first played the game I went to grab a power-up and my ship apparently got enveloped in some sort of a bright and colourful energy ring. I couldn't tell whether that was a good thing that happened because I picked up the power-up or a bad thing caused by an encounter with a nearby enemy bullet. I had to watch the life counter in the top right until it happened again to know for sure that that's what it looks like when my ship explodes. The explosion looks bright, colourful and pretty, and it's not immediately clear it indicates failure.
[1] http://www.thinkwiki.org/wiki/Category:X61s; mine has an L7500 CPU.
[2] http://imgur.com/qpOIwUt
[3] http://imgur.com/gRfi5KV,E6B1oeG